Welding filler metal

Applicable Standards. The following standards are applicable to specifying welding filler metals  

Supplementary Receiving Inspections. The following supplementary receiving inspections, if required, necessitate opening of the package or container to remove a sample  

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Residual stresses caused by large temperature differences between the weld bead and adjacent metal can be reduced by preheating the metals to be welded, especially if the sections are thick, or by stress-relief-annealing following the welding procedure. Proper welding techniques, especially the use of appropriate weld filler metals to minimize weld-metal shrinkage, can minimize residual stresses. 

Sample Specifications 14 in. (35 /2 cm) diameter 316L stainless steel pipe 308L weld filler metal... 

Naphthenic acid corrosion is quite severe in vacuum and visbreaker towers. Crudes with total acid numbers over 2.0 mg KOH/g have corroded type 316 SS in the inlet areas. At times, type 317 (UNS S31700) SS, 904L (UNS N08904), or other corrosion resistant alloys are needed. Matching weld filler metal must be used. In one case, a type 310 (UNS S31000) SS weld filler metal was used on type 316 SS lining. While the strip lining was not attacked, the weld dissolved in one year. 

Sampling. Weld filler metals packages or containers are usually 100% inspected, although the packages or containers must not be opened. 

Metal products are made by distinct manufacturing routes, leading to specific product forms to suit end-user needs. Fundamental differences between wrought, cast, powder metal and weld filler metals have led to different specification systems for such products. Heat treatment is the most important method of strengthening metals although mechanical work is also used. See Figure 5-1. 

Welding filler metals (consumables) are melted and become an integral part of the finished joint. They must tolerate very high cooling rates from the molten state and at the same time possess adequate strength and be free from discontinuities. To achieve such properties, welding filler metals generally have different compositions from the base metals... 

Figure 6-13. Welding filler metals are identified by a stenciled AWS designation at the end of a coated electrode and a paper flag at the end of bare wire.

Welding Filler Metal Wrong filler metal with poorer corrosion resistance (317L stainless steel) was used in alloy C-276 piping Product leakage at welds required shutdown and replacement of piping Check certification of weld filler metals used for field fabrication. For critical applications conduct chemical analysis on sample... 

It is important that the welding filler metal must at least match the contents of the base metal with respect to specific alloying elements such as chromium, nickel, and... 

Singly and combined stainless steel weld filler metals (delta ferrite controlled to 5FN-20FN deposited)... 

The delta ferrite content of each lot and/or heat of weld filler metal used for welding of austenitic stainless steel code components shall be determined for each process to be used in production. Delta ferrite determinations for consumable inserts, electrodes, rod or wire filler metal used with the gas tungsten arc welding process, and deposits made with the plasma arc welding process may be determined by either of the alternative methods of magnetic measurement or chemical analysis described in Section III of the ASME Code. 

Higher-alloy steel having high corrosion and heat resistance. Welding filler metals to compensate for alloy loss in welding, industrial furnaces. 

In some cases, there is preferential attack on weld filler metal in austenitic stainless steels related to its ferrite content. 

Fabrication procedure and surface finish the intrinsic resistance of a material to crevice corrosion m be dramatically hampered by in propriate fabrication procedures. The most sensitive points are welding procedures, which must be optimized by an appropriate energy input and, if necessary, by the use of more alloyed filler metal thermal treatments, particularly if stress rehef has to be performed and surface conditions, which may suffer from fabrication events (scratches with iron incrustation, drops of welding filler metal, etc.) and which should be restored at the end of the fabrication process, for example, by a passivation treatment in the case of stainless alloys. 

High Ni alloys (greater than 35% Ni) used either as base metals or as welding filler metals are a special concern in sulfidation conditions. Sulfidation of high Ni alloys can be especially rapid and yield corrosion... 

Welding. Welding is another processing step that changes the metal structure and can have significant effects on the corrosion behavior of the metal. Galvanic corrosion cells can arise between the weld metal, the heat-affected zone (HAZ), and the parent plate. Weld filler metals can vary in composition, and flux residues can alter the metal surface. In addition, the heat-affected zone of the base metal... 

It has better overall corrosion resistance in oxidizing corrosives than C-4, C-276, and 625 aUoys, outstanding resistance to localized corrosion, and excellent resistance to stress corrosion cracking. It is the best alloy to use as universal weld filler metal to resist corrosion of weldments. 

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