The ferritic steels (carbon, low alloy, and 400 series stainless steels) all undergo a ductile-to-brittle transition as temperature is lowered. Each of these steels has…

Susceptibility of structures to brittle fracture depends on: 1. Preexisting flaw size 2. Tensile stress level 3. Fracture toughness of the material Flaw size and…

Brittle fracture is a sudden, often catastrophic failure which is inherent to “brittle” materials (discussed below). It involves little or no deformation (yielding), and it…

The martensitic stainless steels are especially susceptible to sulfide stress cracking. Welds are difficult to soften with heat treatment and are, therefore, susceptible to cracking.…

At elevated temperatures, all stainless steels with high chromium contents will develop some “sigma phase” which causes embrittlement at lower temperatures. Sigma phase is very…

Straight chromium stainless steels, such as the ferritic (Types 405 and 430) and martensitic types (Type 410), containing 13% or more chromium can embrittle during…

Chloride stress corrosion cracking of austenitic stainless steels (Types 304, 316, 321, 347, etc.) can occur in aqueous solutions containing chloride ions. Cracking is most…

Stainless steels are alloys of iron and chromium, typically with at least 12% chromium. Additionally, the 300 series stainless steels contain nickel. A term commonly…

Carbon-moly steel is similar to carbon steel but with 0.5% molybdenum added. The molybdenum improves the steel’s high temperature strength and graphitization resistance. The corrosion…

Carbon steel with a 1/8- to 1/4-inch corrosion allowance is the economical material selection for a large percentage of pressure vessels in refinery, chemical plant,…