Dampproof hydrogen sulfide stress corrosion steel and preparing method thereof

Abstract

A steel for anti humid hydrogen sulfide stress corrosion and its preparation method, is characterized in the chemical ingredient (weight%) :0.04-0.08 C, 0.20-0.50 Si, 0.30-0.60 Mn, 2.00-2.30 Cr, 0.40- 0.70Al, 0.30-0.45Mo; P<=0.020, S<=0.010, Cu<=0.15, Ni<=0.20, Ti<=0.020, Sn<=0.020, As<=0.020, Pb<=0.0025, Bi<=0.010, Sb<=0.004; (N)<=0.030, (O)<=0.0025, (H)<=0.00015; surplus Fe. Adopting electric furnace primary smelt, vacuum refining in ladle oven, die-casting, heat working rolling cogging, processing with 940 DEG C normalizing and 700 DEG C tempering, finished steel product of anti humid hydrogen sulfide stress corrosion is obtained, whose metallographic structure is ferrite as well as micropearlite, actural grain size is finer than grade 6, and welding performance is good, mechanical performance is good. The inventive finished steel product has characters of high purity, matching with rigidity of crude oil smelt apparatus shell steel sheet, has good SSCC resistance,SCC resistance of chloride ion, and satisfy the need of steel for high sulfur crude oil apparatus.

Description

technical field [0001] The invention belongs to the composition design and preparation of corrosion-resistant alloy steel in the metallurgical industry, in particular to the wet hydrogen sulfide stress-corrosion resistant alloy steel used for high-sulfur crude oil refining equipment. Background technique [0002] The crude oil produced in different regions has high and low sulfur content, the low is less than 0.1% (such as Daqing crude oil in China), and the high is more than 3% (such as Middle East crude oil). Although sulfur exists in various forms in the crude oil (petroleum) refining process, such as elemental sulfur, sulfide, mercaptan, H2S, SO2, SO3, etc., the obvious damage to crude oil refining equipment is: (1) heating Low-temperature dew point corrosion of flue gas below 200°C in the middle and rear of furnace equipment; (2) Stress corrosion of wet H2S in atmospheric and vacuum and catalytic cracking equipment (SCC is the English abbreviation of stress corrosion, S...

AI Technical Summary

Problems solved by technology

In order to achieve the purpose of prolonging the operation period of equipment, some oil refining companies have tried to use 304, 316 and other stainless steel materials, but there are the following shortcomings: (1) The manufacturing cost of crude oil refining equipment such as heat exchangers has increased significantly; (2) when the temperature When the temperature is higher than 50°C, pitting corrosion and Cl ion stress corrosion (SCC) cracking are prone to occur, so that the operating life of crude oil refining equipment has not been significantly improved

[0005] In the 1990s, relevant domestic steel mills, research institutes and refining and chemical companies jointly developed Cr-Al-Mo-V steel and Cr-Al-Mo alloy steel materials with rare earths. Although they have certain moisture resistance H2S However, in practical applications, it is found that these alloy steel materials have poor weldability and are not as hard as the commonly used 16MnR plate (16MnR plate is a common shell material for heat exchangers in refineries). Matching, cracks are easy to initiate at the weld, which affects the service life of crude oil refining equipment in refineries

Therefore, the current steel properties cannot meet the requirements for the use of high-sulfur crude oil refining equipment in refining and chemical enterprises