A kind of high-toughness anti-tempering large-thickness cr-mo steel plate and production method thereof

Abstract

The invention discloses a high-toughness tempering-resistant large-thickness Cr-Mo steel plate and a production method thereof. The steel plate comprises the following chemical components in percentage by weight: 0.12-0.16% of C, 0.41-0.54% of Si, 0.61-0.75% of Mn, not greater than 0.006% of P, not greater than 0.002% of S, 1.16-1.35% of Cr, 0.46-0.58% of Mo, 0.010-0.020% of Ti, 0.020-0.050% of Al, not greater than 0.008% of As, not greater than 0.005% of Sn, not greater than 0.003% of Sb, and the balance Fe and inevitable impurities. The steel plate prepared through a reasonable ingredient design and with the adoption of a production process of converter smelting, continuous casting, controlled rolling and controlled cooling, and two-time normalizing and tempering, has a thickness of 120mm, a structure which is bainite, ferrite and tempered sorbite, a yield strength of not less than 420MPa, a tensile strength of not less than 580MPa, and an impact energy of greater than 100J at -40 DEG C. The steel plate prepared by the production method disclosed by the invention has excellent low-temperature toughness and high-temperature tempering resistance.

Description

technical field [0001] The invention belongs to the field of steel plate production, and in particular relates to a high-toughness tempering-resistant large-thickness Cr-Mo steel plate and a production method thereof Background technique [0002] With the development and technological progress of the petrochemical and coal chemical industry, refining and chemical equipment is becoming larger and larger, and the wall thickness of equipment is increasing, and the performance requirements for steel plates for equipment are becoming more and more stringent. Large-scale Cr-Mo steel pressure vessels have a long manufacturing period. In order to prevent cracking due to welding stress during the manufacturing and maintenance process, the pressure vessel needs to be subjected to multiple high-temperature tempering heat treatments, such as intermediate stress relief heat treatment and overall post-weld stress relief heat treatment. Wait. The increase of wall thickness prolongs the ti...

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Problems solved by technology

[0004] Publication No. CN103334064A "a low yield ratio Cr-Mo steel plate and its production method" patent, added Ni (0.10%≤Ni≤0.20%), Cu (Cu≤0.10%), the thickness of the steel plate is only 30~ 70mm, after tempering at 690°C×20h, the steel plate can only meet the toughness requirement of -10°C; the publication number is CN103320721A "Cr-Mo steel plate requiring thick and high tensile yield and lower limit of strength and its production method" patent , adding Ni (0.10%≤Ni≤0.20%) and Cu (Cu≤0.10%), the thickness of the steel plate is only 20-100mm, and after tempering at 680°C×20h, the steel plate can only meet the toughness requirement of -5°C; Publication number is CN104561837A " a kind of pressure vessel steel ASTMA387CL11Gr2 steel plate and production method thereof " patent, has added Ni (Ni≤0.20%), Cu (Cu≤0.10%), and steel plate thickness reaches 150mm, but adopts steel ingot production, and production cost is relatively high. High, low efficiency, the steel plate can only meet the toughness requirement of 20°C after tempering at 690°C×32h

In the above patents, the impact toughness of the steel plate after high temperature tempering can only reach -10°C

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