API SSAW Spiral Steel Pipe Large Diameter Pipe

The material selection of API SSAW Spiral Steel Pipe Large Diameter Pipe is mainly considered from the following five aspects. Fastener materials in terms of mechanical properties, especially strength requirements, environmental requirements for the corrosion resistance of materials. The requirements of the working temperature on the heat resistance of the data (high temperature strength, oxidation resistance), and the requirements of the production technology on the processing performance of the data.

Other aspects, such as weight, price, and purchase factors must be considered. After screening and comprehensive consideration of these five aspects, the brand, type, specification, and material specification of fasteners are selected. The commonly used models of austenitic stainless steel are 302, 303, 304, 305, the so-called "18-8" type austenitic stainless steel.

Both corrosion resistance and mechanical properties are similar. The action point chosen is the technical method of fastener consumption, the method depends on the size and shape of the fastener, as well as on the quantity consumed. Martensitic stainless steel type and 416 type can be strengthened by heat treatment, the hardness is 35~45HRC, and the machining performance is good. It is used for heat-resistant and corrosion-resistant fasteners for general purposes. Type 416 has a slightly higher sulfur content and is easy to cut stainless steel.

The sulfur content is ≥0.15%, the mechanical properties are improved, the heat treatment is strengthened, and the hardness value is 53~58HRC, which is used for fasteners requiring high strength. Precipitation-hardening stainless steel, PH15-7Mo, is stronger than the usual 18-8 type stainless steel and is therefore used for high-strength, corrosion-resistant stainless steel fasteners. Non-standard stainless steels have higher corrosion resistance than commonly used Type 18-8 stainless steels, and also have good mechanical properties at elevated temperatures.