阅读说明：本技术 一种气化炉用铬钼钢板的焊后热处理工艺 (Postweld heat treatment process of chromium-molybdenum steel plate for gasification furnace ) 是由 李样兵 李建朝 李�杰 袁锦程 吴艳阳 龙杰 庞辉勇 柳付芳 牛红星 尹卫江 侯 于 2020-06-10 设计创作，主要内容包括：一种气化炉用铬钼钢板的焊后热处理工艺,属于冶金技术领域。其包括以下步骤：(1)预热升温：钢板在炉温300～400℃时装炉,匀速升温至600～640℃；(2)一次保温：钢板在600～640℃保温5～7h；(3)二次升温：一次保温结束后钢板不出炉,随即匀速升温至680～705℃；(4)二次保温：钢板在680～705℃保温24～26h；(5)钢板缓冷：二次保温结束后,钢板随炉匀速降温至炉温300～400℃,之后出炉空冷。本发明可显著减少钢板焊后容易在焊缝及热影响区产生热裂纹和延迟裂纹的问题；所得钢板板厚1/2处抗拉强度530-590MPa、-18℃冲击功平均值≥80J,焊后开裂计划外率≤0.6%。(A postweld heat treatment process of a chromium-molybdenum steel plate for a gasification furnace belongs to the technical field of metallurgy. Which comprises the following steps: (1) preheating and warming: charging the steel plate at the furnace temperature of 300-400 ℃, and raising the temperature to 600-640 ℃ at a constant speed; (2) primary heat preservation: the steel plate is subjected to heat preservation for 5-7 h at the temperature of 600-640 ℃; (3) secondary heating: after primary heat preservation is finished, the steel plate is not taken out of the furnace, and then the temperature is uniformly increased to 680-705 ℃; (4) secondary heat preservation: the steel plate is subjected to heat preservation for 24-26 h at 680-705 ℃; (5) slowly cooling the steel plate: and after the secondary heat preservation is finished, the steel plate is cooled to the furnace temperature of 300-400 ℃ along with the furnace at a constant speed, and then the steel plate is taken out of the furnace for air cooling. The invention can obviously reduce the problems that the steel plate is easy to generate hot cracks and delayed cracks in a welding seam and a heat affected zone after being welded; the tensile strength of 530-590MPa at the position of 1/2 mm of the obtained steel plate is more than or equal to 80J on the average value of impact energy at-18 ℃, and the planned external rate of cracking after welding is less than or equal to 0.6 percent.)

1. The postweld heat treatment process of the chromium-molybdenum steel plate for the gasification furnace is characterized by comprising the following steps of:

(1) preheating and warming: charging the steel plate at the furnace temperature of 300-400 ℃, and raising the temperature to 600-640 ℃ at a constant speed;

(2) primary heat preservation: the steel plate is subjected to heat preservation for 5-7 h at the temperature of 600-640 ℃;

(3) secondary heating: after primary heat preservation is finished, the steel plate is not taken out of the furnace, and then the temperature is uniformly increased to 680-705 ℃;

(4) secondary heat preservation: the steel plate is subjected to heat preservation for 24-26 h at 680-705 ℃;

(5) slowly cooling the steel plate: and after the secondary heat preservation is finished, the steel plate is cooled to the furnace temperature of 300-400 ℃ along with the furnace at a constant speed, and then the steel plate is taken out of the furnace for air cooling.

2. The postweld heat treatment process of a chrome molybdenum steel plate for a gasifier as claimed in claim 1, wherein the temperature rise rate in the step (1) is 25-58 ℃/h; the heating rate in the step (3) is 80-220 ℃/h.

3. The postweld heat treatment process of a chromium molybdenum steel plate for a gasification furnace according to claim 2, wherein the cooling rate in the step (5) is 25-58 ℃/h.

4. The postweld heat treatment process of a chromium molybdenum steel plate for a gasification furnace according to claim 3, wherein the steel plate in the step (5) is discharged from the furnace and air-cooled to 20-25 ℃.

5. The post-weld heat treatment process for a chromium molybdenum steel sheet for a gasification furnace according to claim 4, wherein the chromium molybdenum steel sheet has a mark of 14Cr1MoR, in which Cr: 1.45-1.54%, Mo: 0.60 to 0.70 percent.

6. The post-weld heat treatment process for a chromium molybdenum steel sheet for a gasifier according to any one of claims 1 to 5, wherein the thickness of the chromium molybdenum steel sheet is 70 to 150 mm.

7. The postweld heat treatment process of the chromium-molybdenum steel plate for the gasification furnace as claimed in claim 6, wherein the chromium-molybdenum steel plate after the postweld heat treatment process has a tensile strength of 530-590MPa at a position 1/2 ℃ below zero and an average value of impact energy at-18 ℃ of not less than 80J and an planned cracking rate after welding of not more than 0.6%.

Technical Field

The invention belongs to the technical field of metallurgy, and particularly relates to a postweld heat treatment process of a chromium-molybdenum steel plate for a gasification furnace.

Background

Under the situation that the global attention is paid to environmental protection and energy conservation, the structure and the device of the gasification furnace are continuously updated, upgraded and complicated. The water-coal-slurry water-cooled wall waste boiler gasification furnace is the latest generation gasification furnace in China, and a gasification chamber, a radiant steam generator and a chilling chamber of the gasification furnace are directly connected to share one integral shell, so that the gasification furnace is simple in structure and low in investment; the high-quality steam can be obtained as a byproduct by recycling the heat of the high-temperature synthesis gas, the system has high thermal efficiency and good coal adaptability, and can realize the high-efficiency clean utilization of resources such as high ash melting point, high ash content, high sulfur content, high alkali metal content, low volatile coal, semicoke, petroleum coke and the like.

In the existing postweld heat treatment process of the steel plate for the gasification furnace, the steel plate is easily cracked after welding in the heat treatment process due to the fact that the furnace charging is carried out once to the temperature, the high-temperature heat preservation and the discharging from the furnace once to the point are carried out, and the temperature rising and reducing speed is too high, so that the economic loss is caused, and meanwhile, great hidden danger is brought to equipment safety. The problems seriously restrict the development of the gasification furnace industry in China, particularly the waste boiler gasification furnace with the water-coal-slurry water-cooled wall.

Therefore, aiming at the problems, the invention innovates the postweld heat treatment process of the steel plate for the gasification furnace, solves the problems that the steel plate for the gasification furnace is easy to generate hot cracks and delayed cracks in a welding seam and a heat affected zone in the welding process, reduces the production loss and obviously improves the production efficiency.

Disclosure of Invention

In order to solve the technical problem, the invention provides a postweld heat treatment process of a chromium-molybdenum steel plate for a gasification furnace. The invention adopts the following technical scheme:

a postweld heat treatment process of a chromium-molybdenum steel plate for a gasification furnace comprises the following steps:

(1) preheating and warming: charging the steel plate at the furnace temperature of 300-400 ℃, and uniformly heating to 600-640 ℃ at the heating rate of 25-58 ℃/h;

(2) primary heat preservation: the steel plate is subjected to heat preservation for 5-7 h at the temperature of 600-640 ℃;

(3) secondary heating: after primary heat preservation is finished, the steel plate does not come out of the furnace, and is heated to 680-705 ℃ at a constant speed at a heating rate of 80-220 ℃/h;

(4) secondary heat preservation: the steel plate is subjected to heat preservation for 24-26 h at 680-705 ℃;

(5) slowly cooling the steel plate: after the secondary heat preservation is finished, the steel plate is cooled to the furnace temperature of 300-400 ℃ along with the furnace at a constant speed at a cooling rate of 25-58 ℃/h, and then the steel plate is taken out of the furnace and cooled to 20-25 ℃ in air.

The chromium molybdenum steel plate has the mark of 14Cr1MoR, wherein the Cr: 1.45-1.54%, Mo: 0.60 to 0.70 percent.

The thickness of the chromium-molybdenum steel plate is 70-150 mm.

The tensile strength of the chromium-molybdenum steel plate treated by the postweld heat treatment process at the position of 1/2-thickness is 530-590MPa, the average value of impact energy at-18 ℃ is more than or equal to 80J, and the planned outcrop rate of post-weld cracking is less than or equal to 0.6%.

The beneficial effect that adopts above-mentioned technical scheme to produce lies in: according to the invention, a preheating system with a lower heat preservation temperature is added before high-temperature postweld heat treatment, the temperature rising and falling rate is strictly controlled in the whole process, and the problems that the steel plate is easy to generate hot cracks and delayed cracks in a welding seam and a heat affected zone after welding are practically solved. The average value of the impact power at the position of 1/2-DEG C of the tensile strength of 530-590MPa and the average value of the impact power at-18 ℃ of the steel plate treated by the postweld heat treatment process is not less than 80J, the planned rate of cracking after welding is not more than 0.6 percent, and the mechanical property is stable and good; the production cost of a manufacturing enterprise is reduced, and meanwhile, the production operation efficiency is improved.

Detailed Description

The present invention will be described in further detail with reference to examples.