ASME SA335 / ASTM A335, Chrome-Moly pipe is a seamless ferritic Alloy-Steel Pipe produced in nominal or minimum wall thickness for high temperature service. Pipe ordered to this specification shall be suitable for bending, flanging, similar forming operations and for fusion welding.
Chrome Moly products are named so due to the presence of the two elements Molybdenum (Mo) and Chromium (Cr). Cr raises the properties of tensile, yield and hardness (at room ambient temperatures) making it ideal for combatting oxidation in high temperature services. Mo is known, amongst other attributes, to improve the hardenability, reduce brittleness, strengthen the elastic limit, increase temperature strength and improve weldability in certain situations. Sometimes referred to as “P Grade” materials, chrome moly pipe comes in more than 17 grades with the most widely used P-Grades being P5, P9, P11, P22 and P9.
It is commonly known that A335 / SA335 material is extensively used in a variety of plants & processes across the globe including refineries, power plants, petro-chemical plants, hydrocrackers, cokers, high and super high temperature lines, reheat lines, distillation, oil field services, etc. In general, the most commonly used P grades in refineries are P5 & P9. The most commonly used P grades in the power generation industry and petro-chemical plants are P11, P22 & P91. A quick perusal, however, of what appears to be similarly designed facilities will result in findings that they do not necessarily use the same piping specifications. For example, there are many different designs and piping systems in what be generically called a “natural gas processing plant”.
STD, 40, XH, 60, 80, 100, 120, 140, 160, XXH
Wall thicknesses up to 4", intermediate, average and min walls
Chrome moly, ferritic alloy, creep and heat resistant.