L290 spiral steel pipe

L290 spiral steel pipe is an important structural part of machine tools.

L290 is actually a material of pipeline steel pipe. It is the same as the Q235B we usually use to represent the steel grade code, where L represents the pipe for low-pressure fluid transportation, and 290 represents the yield strength of the material is 290MPa, so L290 refers to the yield strength of 290Mpa. Spiral steel pipe for low pressure fluid conveyance.

Chemical composition of L290 spiral steel pipe:
C, ≤ 0.22
Si, ≤ 0.45
Mnb, ≤ 1.30
P, ≤ 0.025
S, ≤ 0.015
V, ≤ 0.05
Nb, ≤ 0.05
Ti, ≤ 0,04

L290 spiral steel pipe heat treatment status:
1. Tempering at low temperature (150-250 degrees)
The structure obtained by low temperature tempering is tempered martensite. Its purpose is to reduce the internal stress and brittleness of the quenched steel while maintaining the high hardness and high wear resistance of the quenched steel, so as to avoid cracking or premature damage during use. It is mainly used for various high-carbon cutting tools, measuring tools, GB/T9711.1 pipeline steel pipes, rolling bearings and carburized parts, etc. The hardness after tempering is generally HRC58-64.
2. Tempering at medium temperature (250-500 degrees) The structure obtained by tempering at medium temperature is tempered troostite. Its purpose is to obtain high yield strength, elastic limit and high toughness. Therefore, it is mainly used for the treatment of various GB/T9711.1 pipeline steel pipes and hot work molds, and the hardness after tempering is generally HRC35-50.
3. High temperature tempering (500-650 degrees)
The structure obtained by high temperature tempering is tempered sorbite. Customarily, the heat treatment combined with quenching and high temperature tempering is called quenching and tempering treatment, and its purpose is to obtain comprehensive mechanical properties with good strength, hardness, plasticity and toughness. Therefore, it is widely used in important structural parts of automobiles, machine tools, etc., such as connecting rods, bolts, gears and shafts. The hardness after tempering is generally HB200-330.

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