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SPECIFICATION FOR WELDING ELECTRODES AND
RODS FOR CAST IRON
SFA-5.
(Identical with AWS Specification A5.15-90)
1. Scope
This specification prescribes requirements for the classification of the following: (a) Rods for oxyfuel gas welding; (b) Electrodes for gas metal arc welding; (c) Electrodes for flux cored arc welding; (d) Electrodes for shielded metal arc welding. These filler metals are suitable for welding gray cast iron, malleable cast iron, nodular cast iron, compacted graphite cast iron, and certain alloy cast irons.^1
PART A — GENERAL REQUIREMENTS
2. Classification
2.1 The electrodes and rods covered by this specifica- tion are classified according to chemical composition, as specified in Tables 1A, 1B, and 1C.
2.2 Electrodes and rods classified under one classifi- cation shall not be classified under any other classifica- tion in this specifications.
2.3 The electrodes and rods classified under this specification are intended for oxyfuel gas welding, shielded metal arc welding, gas metal arc welding, or flux cored arc welding, as applicable, but that is not to prohibit their use with any other process for which they are found suitable.
(^1) Copper-base filler metals frequently used in the braze welding of cast iron are no longer included in this specification. For information pertaining to these materials see A7.6 in the Appendix.
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3. Acceptance Acceptance^2 of the welding electrodes shall be in accordance with the provisions of ANSI /AWS A5.01, Filler Metal Procurement Guidelines.^3 4. Certification By affixing the AWS specification and classification designations to the packaging, or the classification to the product, the manufacturer certifies that the product meets the requirements of this specification.^4 5. Units of Measure and Rounding Off Procedure 5.1 U.S. Customary Units are the standard units of measure in this specification. The SI Units are given as equivalent values to the U.S. Customary Units. The standard sizes and dimensions in the two system are not identical, and for this reason, conversion from a standard size or dimension in one system will not always coincide with a standard size or dimension in the other. Suitable conversions, encompassing standard sizes of both, can be made, however, if appropriate tolerances are applied in each case.
(^2) See section A3 (in the Appendix) for further information concerning acceptance, testing of the material shipped, and ANSI /AWS A5.01, Filler Metal Procurement Guidelines. (^3) AWS standards can be obtained from the American Welding Society, 550 N.W. LeJeune Road, P.O. Box 351040, Miami, Florida 33135. (^4) See Section A4 (in the Appendix) for further information concerning certification and the testing called for to meet this requirement.
SFA-5.15 1998 SECTION II
TABLE 1A (1) CHEMICAL COMPOSITION REQUIREMENTS FOR UNDILUTED WELD METAL FOR SHIELDED METAL ARC AND FLUX CORED ARC WELDING ELECTRODES
Weight Percent (1) (2) (3) Other AWS UNS Elements, Classification(4)^ Number(5)^ C Mn Si P S Fe Ni (6)^ Mo Cu(7)^ Al Total
Shielded Metal Arc Welding Electrodes
ENi-CI W82001 2.0 2.5 4.0... 0.03 8.0 85 min.... 2.5 1.0 1. ENi-CI-A W82003 2.0 2.5 4.0... 0.03 8.0 85 min.... 2.5 1.0–3.0 1. ENiFe-CI W82002 2.0 2.5 4.0... 0.03 Rem. 45–60... 2.5 1.0 1. ENiFe-CI-A W82004 2.0 2.5 4.0... 0.03 Rem. 45–60... 2.5 1.0–3.0 1. ENiFeMn-CI W82006 2.0 10–14 1.0... 0.03 Rem. 35–45... 2.5 1.0 1. ENiCu-A W84001 0.35–0.55 2.3 0.75... 0.025 3.0–6.0 50–60... 35–45... 1. ENiCu-B W84002 0.35–0.55 2.3 0.75... 0.025 3.0–6.0 60–70... 25–35... 1.
Flux Cored Arc Welding Electrodes
ENiFeT3-CI(8)^ W82032 2.0 3.0–5.0 1.0... 0.03 Rem. 45–60... 2.5 1.0 1.
notes follow on next page
TABLE 1B (1) CHEMICAL COMPOSITION REQUIREMENTS FOR CORE WIRE FOR SHIELDED METAL ARC WELDING ELECTRODES
Weight Percent (5) Other AWS UNS Elements, Classification(5)^ Number(5)^ C Mn Si P S Fe Ni Mo Cu Al Total
Shielded Metal Arc Welding Electrodes
ESt K01520 0.15 0.60 0.15 0.04 0.04 Rem................
notes follow on next page
5.2 For the purpose of determining conformance with this specification, an observed or calculated value shall be rounded to the “nearest unit” in the last right-hand place of figures used in expressing the limiting value in accordance with the rounding off method given in ANSI /AWS A1.1, Metric Practice Guide for the Weld- ing Industry.
PART B — TEST, PROCEDURES, AND
REQUIREMENTS
6. Summary of Tests
Chemical analysis, as specified in Table 2, of the filler metal or rod stock from which the filler metal
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is made, or the core wire, or the undiluted weld metal is the only test required for classification of a product under this specification.
7. Retest If the results of any test fail to meet the requirement, that test shall be repeated twice. The results of both tests shall meet the requirements. Specimens for retest may be taken from the original test assembly or sample, or from new test assemblies or samples. For chemical analysis, retest need only be for those specific elements that failed to meet the test requirement.
SFA-5.15 1998 SECTION II
FIG. 1 PAD FOR CHEMICAL ANALYSIS OF UNDILUTED WELD METAL
the completed pad shall be as shown in Fig. 1, for each size of electrode. Testing of this assembly shall be as specified in para. 9.2.
9. Chemical Analysis
9.1 For solid filler metal classified in Table 1A, and the core wire for electrodes classified in Table 1B, a
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sample of the filler metal, core wire, or the rod stock from which the filler metal or core wire is made, shall be prepared for chemical analysis. Solid filler metal, when analyzed for elements that are present in a coating (copper flashing, for example), shall be analyzed without removing the coating. When the filler metal is analyzed for elements other than those in the coating, the coating shall be removed if its presence affects the results of
PART C — SPECIFICATIONS FOR WELDING RODS, ELECTRODES, AND FILLER METALS SFA-5.
the analysis for other elements. Rod stock analyzed for elements not in the coating may be analyzed prior to applying the coating.
9.2 For electrodes classified in Table 1A, a sample shall be analyzed in the form of weld metal, not filler metal. The sample for analysis shall be taken from weld metal obtained with the filler metal. The sample shall come from a weld pad as shown in Fig. 1. The top surface of the pad described in para. 8.3 and shown in Fig. 1 shall be removed, discarded, and a sample for analysis shall be obtained from the underlying metal by any appropriate mechanical means. The sample shall be free of slag. For covered electrodes 1 ⁄ 8 in. (3.2 mm) and smaller and flux cored electrodes .052 in. (1.3 mm) diameter and smaller, the sample shall be taken at least 7 ⁄ 16 in. (11 mm) from the nearest surface of the base metal. For covered electrodes larger than 1 ⁄ 8 in. (3.2 mm) diameter and flux cored electrodes larger than .052 in. (1.3 mm), the sample shall be taken at least 9 ⁄ 16 in. (14 mm) from that surface.
9.3 The sample shall be analyzed by accepted analyti- cal methods. The referee method shall be the appropriate one of the following:^5 (a) ASTM E 39, Standard Method for Chemical Analysis of Nickel; (b) ASTM E 76, Standard Methods for Chemical Analysis of Nickel-Copper Alloys; (c) ASTM E 350, Standard Method for Chemical Analysis of Carbon Steel, Low-Alloy Steel, Silicon Electrical Steel, Ingot Iron and Wrought Iron; (d) ASTM E 351, Standard Methods for Chemical Analysis of Cast Iron—All types; (e) ASTM E 353, Standard Methods for Chemical Analysis of Stainless Heat Resisting, Maraging, and Other Similar Chromium-Nickel-Iron Alloys; (f) ASTM E 354, Standard Method for Chemical Analysis of High Temperature Electric, Magnetic, and Other Similar Iron, Nickel, and Cobalt Alloys.
9.4 The results of the analysis shall meet the require- ments of Table 1 for the classification of filler metal under test.
(^5) ASTM standards can be obtained from the American Society for Testing and Materials, 1916 Race Street, Philadelphia, Pennsylva- nia 19013.
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TABLE 3 STANDARD SIZES AND LENGTHS OF WELDING RODS (1)
Size Length AWS Tolerance, Length, Tolerance, Classification Size, in. in. in. in. (^1) ⁄ 8 round 61 ⁄ 32 18 + 1 ⁄ 2 , − (^1) ⁄ 8 square 61 ⁄ 32 20 + 1 ⁄ 4 , − (^3) ⁄ 16 , 1 ⁄ 4 , RCI (^5) ⁄ 116 ,^3 ⁄^8 ,^61 ⁄^32 24 61 ⁄^4 , − ⁄ 2 , round or square (^1) ⁄ (^8) (^3) ⁄ 16 , 1 ⁄ 4 , RCI-A 5 ⁄ 16 , 3 ⁄ 8 , 61 ⁄ 32 24 + 1 ⁄ 4 , − (^1) ⁄ 2 , round or square (^3) ⁄ 16 , 1 ⁄ 4 , (^3) ⁄ 8 , 1 ⁄ (^2) RCI-B (^) round^1 ⁄ 32 24 + 1 ⁄ 4 , − or square NOTE: (1) Sizes and lengths other than these shall be as agreed to by supplier and purchaser.
SI Equivalents in. mm (^1) ⁄ 32 (0.031) 0. (^1) ⁄ 8 (0.125) 3. (^5) ⁄ 32 (0.156) 4. (^3) ⁄ 16 (0.188) 4. (^1) ⁄ 4 (0.250) 6. (^5) ⁄ 16 (0.313) 8. (^3) ⁄ 8 (0.375) 9. (^1) ⁄ 2 (0.500) 12. 2 51 18 450 20 500 24 600
PART C — MANUFACTURE,
IDENTIFICATION, AND PACKAGING
10. Welding Rods 10.1 Method of Manufacture. The welding rods classified according to this specification may be manu- factured by any method that will produce rods that meet the requirements of this specification.
10.2 Standard Sizes and Lengths. Standard sizes for welding rod shall be as shown in Table 3.
PART C — SPECIFICATIONS FOR WELDING RODS, ELECTRODES, AND FILLER METALS SFA-5.
11.2.2 The diameter of the core wire shall not vary more than 6 0.003 in. (0.08 mm) from the diameter specified. The length shall not vary more than 61 ⁄ 4 in. ( 6 6.4 mm) from that specified.
11.3 Core Wire and Covering 11.3.1 The core wire and covering shall be free of defects that would interfere with uniform deposition of the electrode.
11.3.2 The core wire and covering shall be concen- tric to the extent that the maximum core-plus-one- covering dimension shall not exceed the minimum core- plus-one-covering dimension by more than: (a) seven percent of the mean dimension in sizes (^3) ⁄ 32 in. (2.4 mm) and smaller;
(b) five percent of the mean dimension in sizes 1 ⁄ 8 in. (3.2 mm) and 5 ⁄ 32 in. (4.0 mm), and; (c) four percent of the mean dimension in sizes 3 ⁄ 16 in. (4.8 mm) and larger.
The concentricity may be measured by any suitable means.
11.3.3 The covering of electrodes shall be such that it is not readily damaged by ordinary handling.
11.4 Exposed Core 11.4.1 The grip end of each electrode shall be bare (free of covering) for a distance of not less than (^1) ⁄ 2 in. (12 mm) nor more than 1
4 in. (32 mm) for electrodes 5 ⁄ 32 in. (4.0 mm) and smaller, and not less than 3 ⁄ 4 in. (19 mm) nor more than 1^1 ⁄ 2 in. (38 mm) for electrodes 3 ⁄ 16 in. (4.8 mm) and larger, to provide for electrical contact with the electrode holder.
11.4.2 The arc end of each electrode shall be sufficiently bare and the covering sufficiently tapered to permit easy striking of the arc. The length of the bare portion (measured from the end of the core wire to the location where the full cross-section of the covering is obtained) shall not exceed 1 ⁄ 8 in. (3.2 mm) or the diameter of the core wire, whichever is less. Electrodes with chipped covering near the arc end, baring the core wire no more than the lesser of 1 ⁄ 2 in. (13 mm) or twice the diameter of the core wire, meet the requirements of this specification, provided no chip uncovers more than 50 percent of the circumference of the core.
11.5 Electrode Identification. All electrodes shall be identified as follows:
11.5.1 At least one imprint of the electrode classi- fication shall be applied to the electrode covering within 21 ⁄ 2 in. (65 mm) of the grip end of the electrode.
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11.5.2 The numbers and letters of the imprint shall be bold block type of a size large enough to be legible.
11.5.3 The ink used for imprinting shall provide sufficient contrast with the electrode covering so that in normal use the numbers and letters are legible both before and after welding.
11.5.4 The prefix letter “E” in the electrode classi- fication may be omitted from the imprint.
11.6 Packaging 11.6.1 Electrodes shall be suitably packaged to protect against damage during shipment and storage under normal conditions.
11.6.2 Standard package weights shall be as speci- fied in para. 10.4 or as agreed upon by supplier and purchaser.
11.7 Marking of Packages 11.7.1 The following product information (as a minimum) shall be legibly marked on the outside of each unit package. (a) AWS specification and classification designations (year of issue may be excluded); (b) Supplier’s name and trade designation; (c) Size and net weight; (d) Lot, control, or heat number.
11.7.2 The following precautionary information (as a minimum) shall be prominently displayed in legible print on all packages of electrodes, including individual unit packages enclosed within a larger package:
WARNING:
PROTECT yourself and others.
Read and understand this information.
FUMES AND GASES can be dangerous to
health.
ARC RAYS can injure eyes and burn skin.
ELECTRIC SHOCK can kill.
O Before use read and understand the manufacturer’s instructions, the Material Safety Data Sheets (MSDSs), and your employer’s safety practices. O Keep your head out of the fumes. O Use enough ventilation, exhaust at the arc, or both, to keep fumes and gases away from your breathing zone, and the general area. O Wear correct eye, ear and body protection. O Do not touch live electrical parts.
SFA-5.15 1998 SECTION II
TABLE 5 STANDARD SIZES AND TOLERANCES FOR GAS METAL ARC AND FLUX CORED ARC WELDING ELECTRODES
Standard Standard Sizes Diameter Tolerance Package Form in. mm in. mm Coils With Support... .035 0. Spools... .045 1.1 6 0.002 6 0.
... .052 1. (^1) ⁄ 16 .063 1.
Coils Without Support, 5 ⁄ 64 0.078 2. Coils With Support, 3 ⁄ 32 0.094 2. Spools, 7 ⁄ 64 0.109 2.8 6 0.003 6 0. Drums .120 3.
Coils With Support 1 ⁄ 8 0.125 3. Drums 5 ⁄ 32 0.156 4.0 6 0.004 6 0. GENERAL NOTE: Dimensions and tolerances other than those shown shall be as agreed between the purchaser and supplier.
O See American National Standard Z49.1, Safety in Welding and Cutting, published by the American Welding Society, 550 N.W. LeJeune Road, P.O. Box 351040, Miami, Florida 33135; and OSHA Safety and Health Standards, 29 CFR 1910, avail- able from the Government Printing Office. Wash- ington, DC 20402.
DO NOT REMOVE THIS INFORMATION
12. Gas Metal Arc and Flux Cored Arc Welding Electrodes 12.1 Method of Manufacture. The filler metals classified according to this specification may be manu- factured by any method that will produce filler metals that meet the requirements of this specification.
12.2 Standard Sizes. Standard sizes for filler metal in different package forms (coils with support, coils without support, spools, and drums) shall be as shown in Table 5.
12.3 Finish and Uniformity 12.3.1 All filler metal shall have a smooth finish that is free from slivers, depressions, scratches, scale, seams, laps (exclusive of the longitudinal joint in flux cored electrodes), and foreign matter that would adversely affect the welding characteristics, the opera- tion of the welding equipment, or the properties of the weld metal.
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12.3.2 Each continuous length of filler metal shall be from a single lot of material, and welds, when present, shall have been made so as not to interfere with the uniform, uninterrupted feeding of the filler metal on automatic and semiautomatic equipment.
12.3.3 The core ingredients of flux cored arc welding electrodes shall be distributed with sufficient uniformity throughout the length of the electrode so as not to adversely affect the performance of the electrode or the properties of the weld metal.
12.4 Standard Package Forms 12.4.1 Standard package forms are coil with sup- port, coils without support, spools, and drums. Standard package dimensions and weights for each form are given in Tables 6 and 7. Package forms, sizes, and weights other than these shall be as agreed between purchaser and manufacturer.
12.4.2 The liners in coils with support shall be designed and constructed to prevent distortion of the coil during normal handling and use and shall be clean and dry enough to maintain the cleanliness of the filler metal.
12.4.3 Spools shall be designed (see Fig. 2 and Fig. 3) and constructed to prevent distortion of the filler metal during normal handling and use and shall be clean and dry enough to maintain the cleanliness of the filler metal.
SFA-5.15 1998 SECTION II
FIG. 2 DIMENSIONS OF 12 AND 14 IN. (300 AND 360 MM) SPOOLS
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PART C — SPECIFICATIONS FOR WELDING RODS, ELECTRODES, AND FILLER METALS SFA-5.
FIG. 3 DIMENSIONS OF 30 IN. (760 MM) SPOOLS
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PART C — SPECIFICATIONS FOR WELDING RODS, ELECTRODES, AND FILLER METALS SFA-5.
Appendix
Guide to AWS A5.15-90, Specification for Welding
Electrodes and Rods for Cast Iron
(This Appendix is not a part of ANSI /AWS A5.15-90, Specification for Welding Electrodes and Rods for Cast Iron, but is in- cluded for informational purposes only. 6 )
A1. Introduction
The purpose of this Appendix is to correlate the classifications with their intended applications so the specification can be used effectively. Reference to appro- priate base metal specifications is made whenever that can be done, and when it would be helpful. Such references are intended only as examples rather than complete listings of the base metal for which each filler metal is suitable.
A2. Classification System
A2.1 The system for identifying welding rod and electrode classifications used in this specification follows the standard pattern used in other AWS filler metal specifications. The letter “E” at the beginning of each classification designation stands for electrode, the letters “ER” at the beginning of each classification designation stands for a filler metal which is suitable for use as either an electrode or rod, and the letter “R”at the beginning of each classification designation stands for welding rod. The next letters in the filler metal designa- tion are based on the chemical composition of the filler metal or undiluted weld metal. Thus, NiFe is a nickel- iron alloy, NiCu is a nickel-copper alloy, etc. Where different compositional limits in filler metals of the same alloy family result in more than one classification, the individual classifications are differentiated by the designators “A”or “B”, as in ENiCu-A and ENiCu-B.
(^6) For additional information, refer to AWS D11.2, Guide for Welding Iron Castings.
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A2.2 For flux cored electrodes the designator “T” indicates a tubular electrode. The number “3” indicates that the electrode is used primarily without an external shielding gas. A2.3 Most of the classifications within this specifica- tion contain the usage designator “CI” after the hyphen which indicates that these filler metals are intended for cast iron applications. The usage designator is included to eliminate confusion with other filler metal classifica- tions from other specifications which are designed for alloys other than cast irons. The two exceptions, ENiCu- A and ENiCu-B, preceded the introduction of the usage designator and have never had the “CI” added.
A2.4 The chemical symbols have been used in all the filler metals except the cast iron and mild steel groups. Since there are no chemical symbols for cast iron and mild steel, the letters “CI” and “St” have been assigned to this group to designate cast iron and mild steel filler metals, respectively. The suffixes “A” and “B” are used to differentiate two alloys of the cast iron filler metals from other cast iron rod classifications.
A3. Acceptance A3.1 Acceptance of all welding materials classified under this specification is in accordance with ANSI /AWS A5.01, Filler Metal Procurement Guide- lines, as the specification states. Any testing a purchaser requires of the supplier, for material shipped in accord- ance with this specification, shall be clearly stated in the purchase order, according to the provisions of ANSI /AWS A5.01. In the absence of any such statement in the purchase order, the supplier may ship the material
SFA-5.15 1998 SECTION II
with whatever testing normally conducted on material of that classification, as specified in Schedule F, Table 1, of ANSI /AWS A5.01. Testing in accordance with any other Schedule in that Table shall be specifically required by the purchase order. In such cases, acceptance of the material shipped shall be in accordance with those requirements.
A4. Certification
A4.1 The act of placing the AWS Specification and Classification designations on the packaging enclosing the product, or the classification on the product itself, constitutes the supplier’s (manufacturer’s) certification that the product meets all of the requirements of the specification.
A4.2 The only testing requirement implicit in this certification is that the manufacturer has actually con- ducted the test required by the specification on material that is representative of that being shipped, and that the material met the requirements of the specification. Representative material, in this case, is any production run of that classification using the same formulation. “Certification” is not to be construed to mean that tests of any kind were necessarily conducted on samples of the specific material shipped. Tests on such material may or may not have been made. The basis for the certification required by the specification is the classifi- cation test of “representative material” cited above, and the “Manufacturer’s Quality Assurance System” in ANSI /AWS A5.01.
A5. Ventilation During Welding
A5.1 Five major factors govern the quantity of fumes to which welders and welding operators can be exposed during welding: (a) Dimensions of the space in which welding is done (with special regard to the height of the ceiling); (b) Number of welders and welding operators work- ing in that space; (c) Rate of evolution of fumes, gases, or dusts, according to the materials and processes involved; (d) The proximity of the welder and welding opera- tors to the fumes as the fumes issue from the welding zone, and to the gases and dusts in the space in which they are working; (e) The ventilation provided to the space in which the welding is done.
A5.2 American National Standard Z49.1, Safety in Welding and Cutting (published by the American Weld- ing Society), discusses the ventilation that is required
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during welding and should be referred to for details. Attention is drawn particularly to the section entitled Health Protection and Ventilation.
A6. Welding Considerations A6.1 Welding Considerations for Electrodes A6.1.1 The casting skin should be removed from the weld area by machining, grinding, chipping or other suitable means. When repairing casting defects, care should be exercised to ensure removal of any defective metal to sound base metal before welding. Also, all oil grease, dirt, or other foreign material should be eliminated by the use of suitable solvents. If oil, grease, or solvents have impregnated the casting, heat should be applied to the area to be welded until volatilization is no longer observed. A temperature of 750°F (400°C) generally is sufficient for this operation. If the casting is too greasy, flash heating the welding surfaces to about 1000°F (540°C) should drive off the grease in a gaseous state.
A6.1.2 For V-groove welds, the edges should be beveled to form a 60 to 80 degree groove angle. For very thick base metal, a U-groove weld with a 20- degree groove angle and a groove radius of at least (^3) ⁄ 16 to^
2 in. (4.8 to 13 mm) should be used. A6.1.3 Welding currents should be within the range recommended by the supplier of the electrode, and as low as possible, consistent with smooth operation, good bead contour, and securing good fusion of the groove face. If welding is in other than the flat and horizontal positions, the recommended currents should be reduced to some extent for vertical position and overhead position welding. A6.1.4 The electrode should be manipulated so that the width of the weld bead is no greater than three times the nominal diameter of the electrode being used. If a large cavity must be filled, the sides may be surfaced, and the cavity gradually filled toward the center of the repaired area. A6.1.5 When continuous welding is employed, heat input from the previous passes serves as moderate preheating or to maintain the preheat temperature. Use of preheating is not always necessary, but it is often used. In large castings, it may occasionally be found desirable to use intermittent welding to provide a more even temperature distribution, keeping the casting warm to the touch, but not permitting it to get too hot. A6.1.6 The hardness of the heat-affected zone is a function of the composition and cooling rate of the
SFA-5.15 1998 SECTION II
preferably should be done in a charcoal fire or a furnace. In the case of small castings, however, preheating with a welding torch may be employed.
A6.2.4 A neutral oxyfuel gas flame is preferred for welding cast iron. Some authorities, however, recom- mended the occasional use of a reducing flame where decarburization is to be avoided. A flux is required. The purpose of the flux is to increase the fluidity of the iron silicate slag that forms on the weld pool.
A6.2.5 After the groove has been beveled and cleaned, and the casting preheated, the welding torch is directed over an area extending 1 in. (25 mm) around the weld until the entire area is a dull red. Then the flame is directed at the bottom of the groove, keeping the tip of the cone 1 ⁄ 8 to 1 ⁄ 4 in. (3.2 to 6.4 mm) from the metal, until a weld pool approximately 1 in. ( mm) long has been formed. The flame is then gradually moved from side to side until the groove faces begin to melt into the weld pool. The flame is directed on the rod, and filler metal is added to the weld pool. The groove faces are melted ahead of the advancing pool. The thickness of each layer of weld metal should not exceed 3 ⁄ 8 in. (9.5 mm).
A6.2.6 In the case of rigid structures requiring extensive machining, it is advisable to stress relieve at the preheat temperature after welding. In any case, the casting should be allowed to cool slowly by furnace cooling, or by covering with, or immersion in, an insulating material such as dry sand.
A6.3 Welding Considerations for RCI-B Rods A6.3.1 Preparation of castings for welding is simi- lar to that called for in A6.2.1 and A6.2.2. Preheating should be uniform.
A6.3.2 The application of RCI-B welding rods is the same as that described for the other RCI filler metals. The weld zone can withstand higher residual stresses without cracking. However, it is advisable to apply slow cooling to prevent stress cracks in the base metal. It is recommended that residual stress be reduced by preheating castings uniformly to 1600°F (870°C), and providing slow furnace cooling by covering with, or immersion in, an insulating material such as dry sand. After such treatment, the castings will withstand exposure to considerable thermal expansion and will permit heavy machining.
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A7. Description and Intended Use of Electrodes and Rods for Welding Cast Iron The following are guidelines for the application of welding rods and welding electrodes in conjunction with various types of cast iron. These guidelines are general and subject to modification based on the experi- ence of the welder and information supplied by the filler metal manufacturer. Only rods employed in con- junction with an oxyfuel gas heat source, and electrodes intended for the SMAW, GMAW, or FCAW processes are discussed. This limitation, defined in the scope, is not intended to deter a prospective user from considering other welding processes for which these filler metals might prove satisfactory.
A7.1 Cast Iron Welding Rods A7.1.1 RCI (Cast Iron) Classification A7.1.1.1 Ordinary machinable gray iron castings may vary from 20 to 40 ksi (140 to 280 MPa) tensile strength, and 150 to 250 Brinell hardness. The use of a gray iron welding rod for oxyfuel gas welding can produce a machinable weld metal of the same color, composition and structure as the base metal. The weld, if properly made, may be as strong as the original casting. See Table A1.
A7.1.1.2 RCI welding rods are used for filling in or building up new or worn castings, and for general fabrication, salvage and repair.
A7.1.2 RCI-A (Cast Iron) Classification A7.1.2.1 This cast iron welding rod contains small amounts of molybdenum and nickel, which give it a slightly higher melting point than the ordinary cast iron welding rod, RCI. The molten weld metal is more fluid. Welding can be done more rapidly.
A7.1.2.2 The RCI-A welding rod (with a weld metal hardness of approximately 230 Brinell) may be used if an alloy cast iron is being welded, and when greater tensile strength and finer grain structure are desired. The weld metal is generally considered ma- chinable.
A7.1.3 RCI-B (Nodular Cast Iron) Classification. These nodular (ductile) cast iron welding rods are capable of producing sound weld metal when used to weld higher-strength gray iron, malleable, and nodular iron castings with the oxyfuel gas process. Under optimum conditions, the welds produced have mechani- cal properties of 60 000 psi (410 MPa) minimum ultimate tensile strength; 45 000 psi (310 MPa) mini- mum yield strength; 5 to 15 percent elongation; and
PART C — SPECIFICATIONS FOR WELDING RODS, ELECTRODES, AND FILLER METALS SFA-5.
a maximum Brinell hardness of 200. These mechanical properties are due to the fact that most of the graphite content in the weld metal is in nodular form, which results in good ductility and machining properties for the weld. Color match to the base metal generally is good.
A7.2 Nickel-Base Electrodes for SMAW of Cast Irons. Arc welding with nickel-base covered electrodes is widely employed for welding cast iron. Weld metal made with these electrodes, even without preheating, usually can be machined (the heat affected zone may not be machinable). Welding is fairly rapid when compared to processes such as oxyfuel gas welding. Although welding in the flat position only is required in this specification, some electrodes may be capable of use in other positions. Tensile properties are not specified for the nickel base SMAW electrodes classified in this specification. The tensile and yield strengths may vary widely among manufacturers as shown in Table A1. The filler metal supplier or manufacturer should be contacted for product recommendations.
A7.2.1 ENi-CI (Nickel) Classification. This elec- trode can be used to join ordinary gray irons to themselves, or to other ferrous and nonferrous materials, and to reclaim or repair castings. Satisfactory welds can be produced on small and medium size castings where the welding stresses are not overly severe, or where the phosphorus content of the iron is not high. Because of lower strength than the ENiFe-CI and lower ductility of the weld metal, these electrodes should be used only in applications where maximum machinability of highly diluted filler metal is necessary. Otherwise, the ENiFe-CI classification is preferred. The ENi-CI classification may also be used on malleable or duc- tile iron.
A7.2.2 ENi-CI-A (Nickel) Classification. ENi-CI- A electrodes frequently are used interchangeably with ENi-CI electrodes. The covering of ENi-CI electrodes contains more aluminum to improve operating character- istics such as slag coverage and flowability. However, the aluminum becomes an alloy of the weld metal and may affect ductility.
A7.2.3 ENiFe-CI (Nickel-Iron) Classification. This electrode may be used for making repair welds on, as well as for joining, work pieces of various types of cast iron, including nodular iron, and for welding them to steel and some nonferrous base metals. Castings containing phosphorus levels higher than normal (ap- proximately 0.20% phosphorus) are more readily welded using these electrodes than with an electrode of the ENi- CI classification. Experience has shown that satisfactory
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welds can be made on thick and highly restrained weldments, and on high-strength and engineering grades of cast iron.
A7.2.4 ENiFe-CI-A (Nickel-Iron) Classification. ENiFe-CI-A electrodes frequently are used interchange- ably with ENiFe-CI electrodes. The covering of ENiFe- CI-A electrodes contains more aluminum to improve operating characteristics such as slag coverage and flowability. However, the aluminum becomes an alloy of the weld metal and may affect ductility.
A7.2.5 ENiFeMn-CI (Nickel-Iron Manganese) Classification. This electrode has a nominal addition of 12% manganese to the nickel iron system which improves the flow of the molten metal and somewhat increases the crack resistance of the weld metal. The manganese also increases the tensile strength and im- proves ductility, which provides properties closer to those of the higher strength grades of nodular cast iron base metals than can be achieved with the ENiFe-CI. ENiFeMn-CI electrodes are also used for surfacing to improve wear resistance or for buildup.
A7.2.6 ENiCu-A and ENiCu-B (Nickel-Copper) Classification. These electrodes have been used in many of the same applications as the ENi-Fe-CI, ENiFe- CI-A, and ENiFeMn-CI electrodes. They are used to produce a low depth of fusion weld, since high dilution by the base metal may cause weld cracking.
A7.3 ESt (Steel) Classification for SMAW of Cast Iron A7.3.1 This covered electrode for all welding positions is designed specifically for the welding of cast iron. It has a low-melting-point covering and differs from the ordinary mild steel electrodes included in ANSI /AWS A5.1, Specification for Carbon Steel Elec- trodes for Shielded Metal Arc Welding. Weld metal from this electrode is not readily machinable.
A7.3.2 Since it is virtually impossible to prevent the formation of a hard zone or layer in the weld metal because of dilution from the base metal, this type of electrode is largely confined to the repair of small pits and cracks, with some application in the repair of castings that require no postweld machining. Since the shrinkage of steel is greater than that of cast iron, high stresses develop as the weld cools. Residual stresses may be severe enough to cause cracking.
A7.3.3 Preheating is employed only when neces- sary to prevent excessive stresses in other parts of the casting. ESt electrodes generally are used at low amper- age to minimize the dilution effect in the fusion zone
