Alloy Steel Pipe ASTM A335 P11 Pipe Manufacturing
Alloy steel is a steel alloyed by adding a variety of elements with a total amount between 1.0% and 50% in order to improve its mechanical properties. Alloy steels are divided into two categories: low alloy steels and high alloy steels. The distinction between the two is debatable. Smith and Hashemi defined the difference as 4.0%, while Degarmo et al. defined the difference as 8.0%. Most commonly, the phrase “alloy steel” refers to low alloy steel.
Strictly speaking, every steel is an alloy, but not all steels are called “alloy steels”. The simplest steels are iron (Fe) alloyed with carbon (C) (about 0.1% to 1%, depending on type) and nothing else (excepting negligible traces via slight impurities); these are called carbon steels. However, the term “alloy steel” is the standard term referring to steels with other alloying elements added deliberately in addition to the carbon. Common alloyants include manganese (the most common one), nickel, chromium, molybdenum, vanadium, silicon, and boron. Less common alloyants include aluminium, cobalt, copper, cerium, niobium, titanium, tungsten, tin, zinc, lead, and zirconium.
ASTM A335 P11 Pipe (ASME SA335 P11) is Chrome Moly Alloy Seamless Pipe that used for high-temperature services, P11 Grade Pipe Chrome content at 1.00% to 1.50%, Moly content 0.44% to 0.65%, Minimum tensile strength 415MPa, minimum yield strength 205Mpa.
Chromium and molybdenum are important elements of P11. Chromium, or chrome, improves high-temperature strength, increases oxidation resistance and raises the tensile, yield and hardness at room temperatures. Molybdenum increases the strength, elastic limit, resistance to wear, impact qualities and hardenability. It increases the resistance to softening, restrains grain growth and makes chromium steel less susceptible to embrittlement. Moly is also the most effective additive for increasing high temperature creep strength, or creep resistance. It also enhances the corrosion resistance of steel and inhibits pitting.
