CN-117551854-B - Initiating explosive technology method of marine low-temperature steel plate

CN117551854BCN 117551854 BCN117551854 BCN 117551854BCN-117551854-B

Abstract

A fire engineering process method of a marine low-temperature steel plate comprises the steps of enabling chemical components of the steel to be ：C=0.05%~0.09%、Si=0.10%~0.30%、Mn=1.20%~1.80%、P≤0.008%、S≤0.002%、Al=0.05%~0.08%、Ti≤0.005%、Nb≤0.020%、N=0.0050%~0.0080%、B=0.0010%~0.0025%,% by mass and enabling the balance to be Fe and unavoidable impurities, and enabling the steel plate to be produced by adopting a TMCP process to obtain fine equiaxed ferrite and a small amount of pearlite tissues, wherein the fine equiaxed ferrite and pearlite tissues have good toughness, and the yield strength is more than or equal to 355MPa, the tensile strength is more than or equal to 490MPa, the elongation is more than or equal to 21%, and the impact absorption power at-60 ℃ is more than or equal to 180J. After the steel plate is subjected to the fire work treatment, the microstructure of the steel plate mainly comprises lath bainite, granular bainite and tempered sorbite which are made of fine lath or short bar-shaped ferrite as a matrix, and the strength and the low-temperature impact toughness of the steel plate are not lower than those of a base material. Completely meets the requirements of low-temperature steel and initiating explosive device processing required by the manufacture of ships such as LPG ships and the like.

Inventors

PENG NINGQI
LUO SONGYUN
LI RENGUI
TAN CHANGXIN
TIAN CHONG
AI AIGUO
YANG JIANHUA
LIU XIMAO
GAO QING
ZHOU WENHAO
OU YONG
QIU XIANGFU
Cheng Haoxuan

Assignees

湖南华菱湘潭钢铁有限公司

Dates

Publication Date: 20260512
Application Date: 20230225

Claims (1)

1. A fire engineering process method for a marine low-temperature steel plate is characterized in that the steel is produced by adopting a TMCP process, the heating temperature of a steel billet is 1100-1150 ℃ and the heating time within the temperature range is less than or equal to 120min, the rolling accumulated deformation of a recrystallization region and a non-recrystallization region is controlled to be more than or equal to 90%, the finishing temperature is controlled to be 780+/-20 ℃, the steel is cooled to 650+/-20 ℃ in an accelerated way at a cooling speed of 3-5 ℃ per second after being rolled, and then the steel plate is cooled to room temperature in an air, and the fire engineering process comprises the following steps: (1) Determining a workpiece heating area, marking a boundary line, preparing two jet-suction welding torches, wherein the caliber size of a heating nozzle of a welding torch No. 1 is 3.0mm, and the caliber size of a heating nozzle of a welding torch No. 2 is 1.5mm; (2) The method comprises the steps of firstly heating by a No. 1 welding torch, using acetylene as fuel and adopting neutral flame, controlling the inclination angle of the welding torch to be not smaller than 60 degrees in the heating process, controlling the flame heart distance to be not larger than 3mm, monitoring the flame path temperature by an infrared thermometer, stopping heating and slowly cooling when the surface temperature of a heating area reaches 800+/-10 ℃, reheating by a No. 2 welding torch when the surface temperature of the area is cooled to 700+/-10 ℃, adopting the neutral flame or mild carbonization flame as the fuel, controlling the inclination angle of the welding torch to be 30-60 degrees in the heating process, controlling the flame heart distance to be 2-3 mm until the flame heart distance is heated to a target temperature, and stopping heating and starting air cooling; (3) Heating and then deforming to enable the material to meet the target shape requirement, and if the material cannot meet the target shape requirement, repeating the step (2) until the deformation meets the requirement; (4) Heating the primary flame path again according to the step (2), air-cooling for a period of time after the primary flame path is heated to the target temperature, and then water-cooling by using a water pipe, wherein the water-fire distance is controlled to be 50-80 mm; (5) And (3) after cooling to room temperature, heating the original flame path again by using a No. 2 welding torch, wherein the fuel is propane, a neutral flame is adopted, the inclination angle of the welding torch is controlled to be 20-40 ℃, the flame center distance is 3-4 mm, heating to 650+/-20 ℃, and then air cooling to room temperature.

Description

Initiating explosive technology method of marine low-temperature steel plate Technical Field The invention belongs to the technical field of steel processing, and relates to a fire engineering process method of a marine low-temperature steel plate. Background In recent years, marine cryogenic steel is continuously under service in lower temperature environments, such as LPG marine cryogenic steel is required to be subjected to at least 60 ℃ below zero. For such steels, stable control of performance is a great test, and particularly, in the ship manufacturing process, the steel plate is often corrected and bent by using a fire, or in order to eliminate the poor stress concentration, however, the strength and impact toughness of the steel plate are obviously reduced after passing through the fire. Therefore, the composition and organization design of the marine low-temperature steel in service in the extreme environment and the control of the initiating explosive technology are of great importance. Chinese patent CN114807762A discloses 300MPa grade low temperature steel with excellent low temperature toughness, which comprises, by weight, 0.10% -0.15% of C, 0.20% -0.40% of Si, 1.4% -1.7% of Mn, 0.30% -0.80% of Ni, 0.015% -0.030% of Al, less than or equal to 0.005% of S, less than or equal to 0.008% of P, and the balance of Fe and impurities, wherein 10C+Mn is 2.45% -3%. The steel meets the low-temperature toughness requirement at-80 ℃, but the steel does not relate to the initiating explosive device and has the yield strength of 300 MPa. Chinese patent CN110629111a discloses a low-temperature steel plate for ship with excellent initiating explosive device and its manufacturing method, the main chemical components of which are ：C：0.04%～0.08%,Si：0.15%～0.25%,Mn：0.80%～1.80%,P≤0.012%,S≤0.002%,Als：0.045%～0.070%,N≤0.0040%,Ti：0.005%～0.020%, mass percent and the balance of Fe and unavoidable impurities. The steel is produced by adopting a TMCP process to obtain a refined ferrite and small amount of pearlite structure, the yield strength of the steel before and after a fire is more than 355MPa, and the impact absorption power of the steel at-60 ℃ is more than 120J, but the number of the fire is controlled within 2-3 times to ensure the performance of the steel plate. Disclosure of Invention The patent aims to provide a priming process method for a marine low-temperature steel plate, and the priming process method is adopted by the composition and the tissue design of the marine low-temperature steel, so that the strength and the low-temperature impact toughness of the marine low-temperature steel plate after priming are not lower than those of a base material. The technical scheme of the invention is as follows: A fire engineering process method for a marine low-temperature steel plate comprises the steps of producing the steel plate by adopting a TMCP process, wherein the steel plate is produced by adopting the TMCP process, the heating temperature of a steel billet is 1100-1150 ℃ and the heating time within the temperature range is less than or equal to 120min, controlling the rolling accumulated deformation of a recrystallization region and a non-recrystallization region to be more than or equal to 90%, controlling the final rolling temperature to be 780+/-20 ℃, and cooling to 650+/-20 ℃ at a cooling speed of 3-5 ℃ per second after rolling, and then cooling to room temperature, wherein the fire engineering process comprises the following steps: (1) Determining a workpiece heating area, marking a boundary line, preparing two jet-suction welding torches, wherein the caliber size of a heating nozzle of a welding torch No. 1 is 3.0mm, and the caliber size of a heating nozzle of a welding torch No. 2 is 1.5mm; (2) The method comprises the steps of firstly heating by a No. 1 welding torch, using acetylene as fuel and adopting neutral flame, controlling the inclination angle of the welding torch to be not smaller than 60 degrees in the heating process, controlling the flame heart distance to be not larger than 3mm, monitoring the flame path temperature by an infrared thermometer, stopping heating and slowly cooling when the surface temperature of a heating area reaches 800+/-10 ℃, reheating by a No. 2 welding torch when the surface temperature of the area is cooled to 700+/-10 ℃, adopting the neutral flame or mild carbonization flame as the fuel, controlling the inclination angle of the welding torch to be 30-60 degrees in the heating process, controlling the flame heart distance to be 2-3 mm until the flame heart distance is heated to a target temperature, and stopping heating and starting air cooling; (3) Heating and then deforming to enable the material to meet the target shape requirement, and if the material cannot meet the target shape requirement, repeating the step (2) until the deformation meets the requirement; (4) Heating the primary flame path again according to the step (2), air-cooling for a period of time af