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Rolling method for 35CrMo ultra-thick wall seamless steel pipe

A technology of seamless steel pipes and rolling mills, which is applied in metal rolling and other directions, and can solve problems such as the inapplicability of medium carbon steel

Inactive Publication Date: 2015-03-25
CHANGSHU DONGXIN STEEL PIPE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Medium-carbon steel with poor hardenability, which is widely used in ordinary train axles at home and abroad, is no longer suitable for high-speed trains

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Heat the 35CrMo steel square tube billet to 1200-1260°C in an annular furnace, continue heating for 150-200min, and shape it into a cylindrical billet. On a horizontal hydraulic press, use a 140mm punch to put the heated and shaped billet into the die hole. In the circular punching die, the punch is pressed into the billet, and the solid billet is punched and extruded into a hollow ring billet with a cup bottom by means of reverse extrusion. Roll out inside, extend to remove the bottom of the punching cup, and roll the tube in a pilger mill. When rolling the tube, first blow off the oxide scale in the inner hole of the tube, and add graphite and MoS 2 Mix lubricant, insert the mandrel, enter the rolling mill for rolling, the initial rolling temperature is 1150-1170 ℃, the final rolling temperature is 890-910 ℃, one-time heating and rolling, oxygen cut pilger head, 830±10 ℃ chamber furnace Annealing, hydraulic press pressure straightening, head cut to length.

Embodiment 2

[0018] Heat the 35CrMo steel square tube billet to 1200-1250°C in an annular furnace, continue heating for 150-180 minutes, and shape it into a cylindrical billet. On a horizontal hydraulic press, use a 140mm punch to put the heated and shaped billet into the die hole. In the circular punching die, the punch is pressed into the billet, and the solid billet is punched and extruded into a hollow ring billet with a cup bottom by means of reverse extrusion. Roll out inside, extend to remove the bottom of the punching cup, and roll the tube in a pilger mill. When rolling the tube, first blow off the oxide scale in the inner hole of the tube, and add graphite and MoS 2 Mix lubricant, insert the mandrel, enter the rolling mill for rolling, the initial rolling temperature is 1150-1160 °C, the final rolling temperature is 890-900 °C, one-time heating rolling, oxygen cut Pilger head, 830±10 °C chamber furnace Annealing, hydraulic press pressure straightening, head cut to length.

Embodiment 3

[0020] Heat the 35CrMo steel square tube billet to 1250-1260°C in an annular furnace, continue heating for 180-200min, and shape it into a cylindrical billet. On a horizontal hydraulic press, use a 140mm punch to put the heated and shaped billet into the die hole. In the circular punching die, the punch is pressed into the billet, and the solid billet is punched and extruded into a hollow ring billet with a cup bottom by means of reverse extrusion. Roll out inside, extend to remove the bottom of the punching cup, and roll the tube in a pilger mill. When rolling the tube, first blow off the oxide scale in the inner hole of the tube, and add graphite and MoS 2 Mix the lubricant, insert the mandrel, enter the rolling mill for rolling, the initial rolling temperature is 1160°C, the final rolling temperature is 900°C, one-time heating rolling, oxygen cutting Pilger head, 830±10°C chamber furnace annealing, hydraulic pressure Straighten, go to the head to measure.

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PUM

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Abstract

The invention discloses a rolling method for a 35CrMo ultra-thick wall seamless steel pipe. The rolling method comprises the following steps: continuously heating an annular furnace of a 35CrMo square pipe blank to 1,200-1,260 DEG C for 150-200 minutes, shaping into a cylindrical blank, punching a central hole, extending to remove a punched cup bottom, performing pipe rolling by a Pilger rolling machine, performing oxyacetylene cutting on a Pilger head, performing chamber furnace annealing at 830+ / -10 DEG C, performing pressure straightening on an oil press, removing the head and sizing. According to the rolling method, the 35CrMo ultra-thick wall seamless steel pipe of which the quality meets the technical requirements can be produced by the Pilger rolling machine.

Description

technical field [0001] The invention belongs to the technical field of steel pipes and relates to a rolling method for ultra-thick wall seamless steel pipes of 35CrMo steel. Background technique [0002] High-speed trains are an important indicator of the level of development of railway technology in industrial countries. After six major speed increases in domestic railways, the speed of mainline trains has reached more than 200km per hour. Thereby, many materials on the train, especially the axle material need to be improved and improved. Medium-carbon steel with poor hardenability, which is widely used in ordinary train axles at home and abroad, is no longer suitable for high-speed trains. In order to solve this problem, after considering many factors such as axle load, failure cause, stress distribution characteristics and stress state in operation, the required comprehensive mechanical properties and heat treatment process, according to the development status of foreign...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21B19/04
Inventor 须晓东
Owner CHANGSHU DONGXIN STEEL PIPE