Alloy pipes can be divided into three categories according to the content of alloy elements in the composition:
1. Low alloy pipes: The total content of alloy elements is ≤5%, mainly manganese, chromium, molybdenum, etc. Typical materials include Q345 (GB/T 1591), 16Mn (GB/T 6479), A335 P11 (ASTM). It has high strength and weldability and is widely used in oil pipelines and building structures.
2. Medium alloy pipes: The alloy content is 5%-10%, such as 15CrMo (GB/T 3077), with outstanding high temperature resistance, suitable for boilers and chemical equipment.
3. High alloy pipes: The alloy content is ≥10%, typically represented by 304 stainless steel (0Cr18Ni9, GB/T 14976), with strong corrosion resistance, used in the food and pharmaceutical industries.
Data support: According to GB/T 3077-2015, the yield strength of low alloy steel Q345 is 345MPa (reference standard clause 6.2.1); the chromium content of ASTM A335 P11 is 1.0%-1.5% (standard table 1).
