Low-temperature stainless steel and heat treatment method thereof

Abstract

The invention discloses a low-temperature stainless steel and a heat treatment method thereof. The low-temperature stainless steel comprises components by weight percentage as follows: C less than or equal to 0.03, Mn less than or equal to 2, Si less than or equal to 1, P less than or equal to 0.04, S less than or equal to 0.01, Ni in the range of 8.0-13.0, Cr in the range of 18.0-20, and the rest of Fe and inevitable impurities . The low-tempearture stainless steel heat treatment method comprises the following steps of: placing a steel plate or steel pipe in a heat treatment furnace for heat treatment; integrally heating the steel plate or steel pipe to 1,050-1,080 DEG C; and preserving heat for at least 30 minutes, and the heat preservation time prolongs 2.3-2.6 minutes for every 1 millimeter increase in the wall thickness of the steel plate or steel pipe. In the low-temperature stainless steel disclosed by the invention, the content of S is 0.03% far less than standard content, and the low-temperature stainless steel has better performance. A material obtained according to the low-temperature stainless steel heat treatment method is more uniform in texture distribution and grain, and the strength of a stainless steel pipe is effectively improved.

Description

technical field [0001] The invention relates to the field of stainless steel processing, in particular to a low-temperature stainless steel and a heat treatment method thereof. Background technique [0002] With the continuous promotion of the use of clean energy, the use of natural gas in China continues to increase. Natural gas is clean, efficient and ecologically friendly. The use of natural gas can effectively improve the current ecological environment and the atmospheric environment under the increasingly serious pollution. Therefore, natural gas plays an important role in Guo Ming's economy. The use in is becoming more and more extensive. In order to facilitate storage and transportation, natural gas will be liquefied to become liquefied natural gas (LNG). The main component of LNG is methane, and the boiling point of methane at normal pressure is -161°C. To process LNG from natural gas at normal temperature, it must be processed by a set of cryogenic equipment. Afte...

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Problems solved by technology

As a pipe fitting in a cryogenic device, the selection of material and the production process are very important. The key used in the existing cryogenic device is mainly chromium-nickel austenitic stainless steel, while the existing chromium-nickel austenitic stainless steel The sulfur content of the material is too high, and it cannot be fully dissolved in the smelting process. The stainless steel material produced has low strength, poor low-temperature impact resistance, and cannot meet the requirements of higher strength.