The quality control method of chrome-molybdenum series round tube billets with a diameter of φ280mm

A quality control method, the technology of round tube blanks, which is applied in the field of iron and steel metallurgy, can solve the problems of low heat transfer efficiency, small specific surface area, and difficult control of the internal quality of the casting slab, and achieve the expansion of the area, the improvement of the porosity rating, and the quality of rolled products Well-controlled and stable effect

Active Publication Date: 2018-06-05
PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Furthermore, due to the relatively large cross-section of the slab and its circular slab, the specific surface area of ​​the slab is smaller and the heat transfer efficiency of the slab is lower, making it more difficult to control the internal quality of the slab

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] A steelmaking plant adopts 120t converter smelting → LF furnace refining → RH refining → six-machine six-strand casting machine φ280mm section continuous casting to produce 30CrMo series round tube blanks. At the end of converter blowing, the end point carbon is controlled at 0.10%, and the end point temperature is controlled at 1675°C; the small platform is fed into the aluminum wire at 1.7m / t steel for deoxidation; the mass percentage of the outbound composition of the small platform is controlled as: [C]0.28 %, [Si] 0.21%, [Mn] 1.25%, [P] 0.011%; after deoxidation and alloying, carry out soft blowing argon stirring, stirring time 3.5min, stirring does not appear bare molten steel.

[0026] When the molten steel reaches the LF refining furnace, the molten steel fluctuates slightly after argon blowing, and there is no big turning phenomenon. After the refining is completed, Ti is added at 0.026% of the weight of the molten steel; 7.5 minutes of soft blowing and stirrin...

Embodiment 2

[0031] A steelmaking plant adopts 120t converter smelting → LF furnace refining → RH refining → six-machine six-strand casting machine φ280mm section continuous casting to produce 35CrMo series round tube blanks. At the end of converter blowing, the end carbon is controlled at 0.05%, and the end temperature is controlled at 1680°C; the small platform is 2.0m / t 钢 Feed aluminum wire for deoxidation; outbound components of the small platform are controlled as follows: [C] 0.30%, [Si] 0.18%, [Mn] 1.30%, [P] 0.012%; The time is 4.0min, and the molten steel is not exposed when stirring.

[0032] When the molten steel reaches the LF refining furnace, the molten steel fluctuates slightly after argon blowing, and there is no big turning phenomenon. After refining, Ti is added at 0.035% of the weight of the molten steel; 7.5 minutes of soft blowing and stirring were carried out after the wire feeding, and the temperature of LF exiting the station was 1600°C.

[0033] After the molten ...

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PUM

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Abstract

The invention discloses a method for controlling the internal quality of a Cr-Mo series circular tube steel casting blank with a phi-280mm production section, and belongs to the field of metallurgy. The method comprises the steps such as smelting in a converter, molten steel refining in an LF furnace, RH refining, and continuous casting of molten steel. First of all, the purity of the molten steel is improved according to reasonable parameter control in the molten steel smelting stage, and the high-temperature plasticity of the molten steel is improved and the steel grade crack sensitivity is lowered after the molten steel is subjected to titanium micro-alloying; and then, mold electromagnetic stirring and final electromagnetic stirring are combined in the molten steel pouring stage, so that component and temperature homogenization of the molten steel can be achieved, the shell of the circular tube steel casting blank can grow uniformly, the solidification structure of the circular tube steel casting blank can be effectively improved, the loose level can be raised, the area of an equiaxial crystal region can be enlarged, the compactness of the central region of the circular tube steel casting blank can be effectively improved, the crack defect of the circular tube steel casting blank can be effectively controlled, the surface non-clearing rate can be improved, and the quality of such a rolled product can be controlled well and stably.

Description

technical field [0001] The invention relates to the field of iron and steel metallurgy, in particular to a method for controlling the quality of chrome-molybdenum series round tube blanks with a production scale section of φ280mm. Background technique [0002] Chromium-molybdenum series tube billet steel is mainly used in the production of oil well pipe steel for oil and gas exploitation and transportation. Under the joint action of stress and hydrogen sulfide gas during use, it often occurs suddenly when the force is much lower than its own yield strength. Brittle fracture (called hydrogen sulfide stress corrosion) often causes problems such as production leakage, which has an adverse effect on production and environmental protection. With the development of society and economy, the development trends such as higher requirements for oil and gas transportation efficiency and increased mining difficulty continue to put forward more stringent requirements for the quality of bi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C5/30C21C7/072C21C7/10B22D11/18B22D11/16B22D11/115B22D11/22
CPCB22D11/115B22D11/16B22D11/18B22D11/22B22D11/225C21C5/30C21C7/0006C21C7/0056C21C7/072C21C7/10
Inventor 陈天明李红光郭华李扬洲陈亮郭奠荣杨文中李志强冯远超
Owner PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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