Stress corrosion cracking alloys

M.O. Speidel, Corrosion Fatigue in Fe-Ni-Cr Alloys, Stress Corrosion Cracking and Hydrogen Emhrittlemment in Iron Base Alloys NACE 5, R.W. Staehle, J.H. Hochman, R.D. McCrigh, and J.E. Slater, Ed., National Association of Corrosion Engineers, 1973, p 1071-1080... 

Brass Pitting Cavitation De-alloying Stress corrosion cracking Concentration cell... 

Yau, T. L., Stress-Corrosion Cracking of Zirconium Alloys, Stress-Corrosion Cracking, R. H. Jones, Ed., ASM International, Metals Park, OH, 1992, pp. 299-311. 

Methanol/ Ti-811 exhibits transgranxilar SCC in metha-Water SCC nol like many other titanium alloys. Stress-corrosion cracking in pure methanol is difficult to observe for many susceptible titemium alloys, but it is more prone for Ti-811. The minimum level of water required for fiill SCC inhibition depends on... 

M.J. Blackburn, W.H.Smyrl, and J A Sweeny, Titanivun Alloys, Stress Corrosion Cracking in High Strength Steels and in Titanium and in Aluminum Alloys, B.F. Brown, Ed., Naval Research Laboratory, 1972, p 246-363... 

BEESWAX. Contains about 80% myricin. Beeswax has been used as a protective coating for aluminum alloy stress corrosion cracking test fixtures. See also Ref (Dp. 127. (3)p. 225. 

Stainless steel alloys show exceUent corrosion resistance to HCl gas up to a temperature of 400°C. However, these are normally not recommended for process equipment owing to stress corrosion cracking during periods of cooling and shut down. The corrosion rate of Monel is similar to that of mild steel. Pure (99.6%) nickel and high nickel alloys such as Inconel 600 can be used for operation at temperatures up to 525°C where the corrosion rate is reported to be about 0.08 cm/yr (see Nickel and nickel alloys). 

Many instances of intergranular stress corrosion cracking (IGSCC) of stainless steel and nickel-based alloys have occurred in the reactor water systems of BWRs. IGSCC, first observed in the recirculation piping systems (21) and later in reactor vessel internal components, has been observed primarily in the weld heat-affected zone of Type 304 stainless steel. 

Corrosion control requires a change in either the metal or the environment. The first approach, changing the metal, is expensive. Also, highly alloyed materials, which are resistant to general corrosion, are more prone to failure by localized corrosion mechanisms such as stress corrosion cracking. 

Excellent resistance to saltwater corrosion and biofouling are notable attributes of copper and its dilute alloys. High resistance to atmospheric corrosion and stress corrosion cracking, combined with high conductivity, favor use in electrical/electronic appHcations. 

Brasses are susceptible to dezincification in aqueous solutions when they contain >15 wt% zinc. Stress corrosion cracking susceptibiUty is also significant above 15 wt % zinc. Over the years, other elements have been added to the Cu—Zn base alloys to improve corrosion resistance. For example, a small addition of arsenic or phosphoms helps prevent dezincification to make brasses more usefiil in tubing appHcations. 

Standard Test Methods for Use ofMattsson s Solution of pH 7.2 to Evaluate the Stress Corrosion Cracking Susceptibility of Copper—Zinc Alloys, ASTM G 37-85, American Society for Testing and Materials, Philadelphia, Pa., 1992. 

Virtuallv evety alloy system has its specific environment conditions which will prodiice stress-corrosion cracking, and the time of exposure required to produce failure will vary from minutes to years. Typical examples include cracking of cold-formed brass in ammonia environments, cracking of austenitic stainless steels in the presence of chlorides, cracking of Monel in hydrofluosihcic acid, and caustic embrittlement cracking of steel in caustic solutions. 

Fracture Mechanics Methods These have proved very usebd for defining the minimum stress intensity K[scc. t which stress corrosion cracking of high-strength, low-ductihty alloys occurs. They have so far been less successful when apphed to high-ductility alloys, which are extensively used in the chemicm-process industries. 

---