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A method to overcome the cracking defects of 4140 steel tubing hanger body

An oil pipe hanging and body technology, which is applied in the field of workpiece forging, can solve problems such as pattern defects of folding knives, and achieve the effects of avoiding transgranular expansion, reducing stress cracks, and reducing knife patterns.

Active Publication Date: 2022-03-01
NANJING DEV ADVANCED MFG
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Problems solved by technology

[0006] Based on the above, in view of the macroscopic characteristics of the cracks on the main body of the pendant, the macro-microscopic morphology of the open crack fracture and the inspection results of the metallographic samples taken, there is a folding knife pattern defect at the transition arc of the steps of the main body of the pendant.

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  • A method to overcome the cracking defects of 4140 steel tubing hanger body
  • A method to overcome the cracking defects of 4140 steel tubing hanger body

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Embodiment Construction

[0025] The present invention is described in further detail now in conjunction with accompanying drawing.

[0026] Such as figure 1 Shown, a kind of method of the present invention overcomes the defect of 4140 steel tubing hanger body bursting, comprises

[0027] Step 1: Select 350 square meters of 4140 blanks and put them into the heating furnace; set the temperature at 500±10°C, open the furnace door ajar, set the heating rate at 100°C / hour, and wait until the temperature in the furnace reaches 500±10°C , close the furnace door, and keep warm for two hours.

[0028] The temperature is set at 800±10°C, the heating rate is set at 50°C / hour, and when the temperature in the furnace reaches 800±10°C, keep warm for two hours.

[0029] The temperature is set at 1250±10°C, and the heating rate is set at 25°C / hour. When the temperature in the furnace reaches 1250±10°C, keep warm for two hours before leaving the oven.

[0030] Step 2: Rough machining of the blank, including elongat...

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Abstract

The invention relates to a method for overcoming the cracking defects of the 4140 steel oil pipe hanger body. Firstly, the blank is heated in sections, then the basic process is prepared, and then the mold is forged, and then cooled with lime sand, and finally the formed workpiece is quenched and tempered. heat treatment. This application heats the billet slowly to make the internal structure change slowly, which plays the role of grain refinement and uniform structure. The actual grain size can reach 7 to 10 grades, avoiding the Widmanstatten caused by overheating and overheating. organizations and other harmful organizations. The die forging method is used to avoid excessive surface stress caused by free forging hammer forging. It is forged from multiple directions successively to increase the fluidity of the billet and avoid the generation of knife patterns and the formation of main cracks. In the final quenching, slow down the quenching cooling rate and reduce the cooling rate in the martensite transformation zone, thereby avoiding transgranular expansion, reducing the structural stress of martensite transformation, and avoiding macroscopic cracks.

Description

technical field [0001] The invention relates to a method for overcoming the cracking defect of a 4140 steel oil pipe hanger body, and belongs to the technical field of workpiece forging. Background technique [0002] The 350 m3 4140 billet was forged with a 3t forging hammer to form the body of the oil pipe hanger. The forged billet of the hanger body was subjected to final quenching and tempering heat treatment after rough machining. In order to find out the cause of the defect, one of them was dissected and sampled for inspection. [0003] After investigation and research, it was found that the cracks on the main body of the pendant were ring cracks and longitudinal cracks coexisting, and the cracks were rigid and straight. The annular cracks are located at the transition arc of the steps and distributed along the circumference. The longitudinal cracks are connected with the annular cracks at the first large step and distributed along the radial direction. Regardless of...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23P15/00
CPCB23P15/00
Inventor 陈昌华陈海山汪海潮张利张洪孔德贵刘晓磊哈曜陈新华施虹屹龚洋道陈洁
Owner NANJING DEV ADVANCED MFG
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