Stainless steels welding

Considering the success of detecting crack tip echoes from defects at the near probe surface, future work will deal with the detection and sizing of defects on the far probe surface. Future work also relates to carrying out defect sizing in anisotropic austenitic stainless steel welds and... 

Cautions. Certain types of stainless steel welds are metallurgically designed to form two compositionaUy distinct phases to reduce the... 

Figure 15.9 Cross section of stainless steel weld showing crevice corrosion along a site of incomplete fusion. (Magnification 15x.)...

Galvanic corrosion may occur at stainless steel welds if sensitization has taken place or if welding has produced unfavorable dissimilar phases (see Chap. 15, Weld Defects, particularly Case History 15.1). These forms of microstructural galvanic corrosion do not involve the joining of two different metals in the usual sense. 

Fumes from stainless steel welding Stainless steel fabrication operations... 

Sandor, P., Resistance to Intercrystalline Corrosion in Stainless Steel Weld Metal , Anticorros. 

The corrosion of stainless steel welds has probably been studied more fully than any other form of joint corrosion and the field has been well reviewed by Pinnow and Moskowitz , whilst extensive interest is currently being shown by workers at The Welding Institute. Satisfactory corrosion resistance for a well-defined application is not impossible when the austenitic and other types of stainless steels are fusion or resistance welded in fact, tolerable properties are more regularly obtained than might be envisaged. The main problems that might be encountered are weld decay, knifeline attack and stress-corrosion cracking (Fig. 9.29). 

Fig. 9.29 Corrosion sites in stainless steel welds. The typical peak temperatures attained during welding (°C) are given at the foot of the diagram. Note that knifeline attack has the appearance of a sharply defined line adjacent to the fusion zone...

The Standards, Measurements and Testing Programme of the European Commission launched a few years ago a project dealing with the development and, ultimately, the production of air filters realistically exposed to welding dust occurring during stainless steel welding (Christensen et al. 1999). This project resulted in the production and certification of a batch of 1100 filters for the Cr (VI) content (40.16 0.60 pg/g dust) (CRM 545). In addition, the total leachable Cr content ( 39.37 1.30 pg/g dust) was certified as a means to check for total Cr recovery. 

Report on the Effect of Stainless Steel Weld Overlay or Cladding on Hydrogen Attack of Underlying Steel, Materials Properties Council, New York, September 1984. 

Kalliomaki PL, Hyvarinen KH, Aitio A, et al. 1986. Kinetics of the metal components of intratracheally instilled stainless steel welding fume suspensions in rats. Br J Ind Med 43 112-119. 

Kilbum KH, Warshaw R, Boylen CT, et al. 1990. Cross-shift and chronic effects of stainless-steel welding related to internal dosimetry of chromium and nickel. Am J Ind Med 17 607-615. 

Stainless steel welds should provide reliable joints that are internally smooth and corrosion free. Low carbon stainless steel, compatible... 

Pebble Mill where flint rock media (as opposed to normal steel balls) is used against which the mill s interior is protected by a 75 mm rubber lining over a metal sandwich of 6 mm stainless steel, welded to 60-100 mm carbon steel plate [6]. 

Total chromium and Cr in samples of stainless steel welding dusts were determined after extraction of the samples with a pH 4 buffer solution (Girard and Hubert, 1996). The analytical method involved the use of an FI system equipped with two detectors. The first detector (spectrophotometer) measured Crvl as the diphenylcarbazide complex. The second detector (AA spectrometer) measured total chromium. The recovery of chromium was 96%, and the lower detection limit was 0.005 mg ml-1. 

Occupational exposure to chromium(VI) and/or chromium(III) in other chromium-related industries has also been associated with respiratory effects. These industries include chromate and dichromate production, stainless steel welding, and possibly ferrochromium production and chromite mining. 

Occupational exposure to chromium(VI) compounds in a number of industries has been associated with increased risk of respiratory system cancers, primarily bronchogenic and nasal. Among the industries investigated in retrospective mortality studies are chromate production, chromate pigment production and use, chrome plating, stainless steel welding, ferrochromium alloy production, and leather tanning. 

Human lymphocytes Chromosomal aberrations + Koshi et al. 1984 Sarto et al. 1982 (VI) Stainless steel, welding fumes, chromium trioxide... 

A list of industries that may be sources of chromium exposure is given in Table 5-5. For most occupations, exposure is due to both chromium(III) and chromium(VI) present as soluble and insoluble fractions. However, exceptions include the tanning industry, where exposure is mostly from soluble chromium(in) and the plating industry, where exposure is due to soluble chromium(VI). The typical concentration ranges of airborne chromium(VI) to which workers in these industries were exposed during an average of 5-20 years of employment were chromate production, 100-500 pg/m3 stainless steel welding,... 

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