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A kind of 40cr hot-rolled round steel and production method thereof

A production method and technology for round steel, applied in the field of ferroalloy smelting, can solve the problems of raw materials that cannot be used as pipe blanks, waste of energy and materials, low impact toughness, etc. Effect

Active Publication Date: 2019-11-01
TIANJIN RONGCHENG UNITED IRON & STEEL GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The general hot-rolled round steel has poor impact toughness during hot rolling due to the composition of molten steel in the refining process, showing folds, cracks, and surface defects of oxidized decarburization on the surface of the cast slab, as well as surface defects caused by tension after hot rolling. Too many surface defects that cause scratches or cracks, because hot-rolled round steel with a larger diameter is generally used as a raw material for pipe fittings, when the above-mentioned surface defects exist on the surface and corrosion occurs deep in the hot-rolled round steel , it can not be used as a raw material for pipe fitting blanks due to the possible structural strength problem of low internal impact toughness, and can only be downgraded or returned to the furnace as a scrap steel raw material, resulting in waste of energy and materials, which needs to be improved

Method used

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  • A kind of 40cr hot-rolled round steel and production method thereof
  • A kind of 40cr hot-rolled round steel and production method thereof
  • A kind of 40cr hot-rolled round steel and production method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1A

[0046] A kind of production method of 40Cr hot-rolled round steel, comprises the steps:

[0047] S1 Smelting: Put molten iron and steel scrap into the converter, carry out conventional top-bottom compound blowing and control the blowing oxygen pressure to 0.8MPa, when the tapping temperature is 1623°C, detect the carbon content in the molten steel, and control the carbon at the end of the converter to 0.15wt %, then tap steel into the ladle;

[0048] S2 deoxidation alloying: The converter blows argon throughout the process of tapping into the ladle. When the molten steel in the ladle reaches 1 / 4 of the maximum capacity of the molten steel in the ladle, add carbon powder of 0.33kg / ton of steel and 9.00kg / ton of steel into the ladle. Silicon-manganese alloy of steel, 13.75kg / ton of high-carbon ferrochrome steel, 12.50kg / ton of steel vanadium-iron alloy powder, 11.67kg / ton of steel yttrium-iron alloy powder and 14.17kg / ton of steel tantalum-iron alloy powder, and in the ladle Ad...

Embodiment 1B-1L

[0056] On the basis of Example 1A, the amount of carbon powder, silicon-manganese alloy, high-carbon ferrochrome, vanadium-iron alloy powder, yttrium-iron alloy powder, tantalum-iron alloy powder, lime, limestone and fluorite was changed to produce 40Cr hot-rolled round steel.

[0057] The composition of the 40Cr hot-rolled round steel obtained in Examples 1A-1L is tested. If it meets the composition requirements, it is recorded as 1, and if it does not meet the composition requirements, it is recorded as 0. The composition requirements are C: 0.37-0.44wt%, Si: 0.17-0.37 wt%, Mn: 0.50-0.80wt%, V: 0.32-0.35wt%, P: ≤0.025wt%, Y: 0.2-0.25wt%, S: ≤0.025wt%, Cr: 0.8-1.10wt%, Ta Al: 0.3-0.54wt%, Al: 0.010-0.025wt%, the rest is Fe and unavoidable impurities. The composition test results are shown in the table below,

[0058]

[0059]

[0060] It can be seen from the above that the 40Cr hot-rolled round steel produced by this method meets the composition requirements.

Embodiment 2A

[0067] On the basis of Example 1A, 1.0 kg / ton of steel-aluminium-iron was added to the S1 converter before tapping.

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PUM

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Abstract

The invention relates to the field of iron alloy smelting, and discloses 40Cr hot-rolled round steel and a production method thereof. According to the technical scheme of the 40Cr hot-rolled round steel, smelting, alloy deoxygenization, LF refining, molten steel casting, steel billet heating, hot rolling, controlled cooling after rolling and rolled steel refining are carried out so as to obtain the round steel, the round steel is composed of the following components, by weight percentage: 0.37%-0.44wt% of C, 0.17-0.37wt% of Si, 0.50-0.80wt% of Mn, 0.32-0.35wt% of V, less than or equal to 0.025wt% of P, 0.2-0.25wt% of Y, less than or equal to 0.025wt% of S, 0.8-1.10wt% of Cr, 0.3-0.54wt% of Ta, 0.010-0.025wt% of Al and the balance of Fe and inevitable impurities, the 40Cr hot-rolled round steel with stable components is continuously produced and has good impact toughness, corrosion resistance and rust resistance, and therefore generation of waste steel in the production process and thestorage process can be reduced, the energy consumption and material consumption can be reduced, the production cost can be lowered, and the economic benefits of products can be improved.

Description

technical field [0001] The invention relates to the field of ferroalloy smelting, in particular to a 40Cr hot-rolled round steel and a production method thereof. Background technique [0002] Hot-rolled round steel is a kind of round steel. Its specification is 5.5-250 mm. It has the characteristics of good hardenability, high hardness, good wear resistance, and small heat treatment deformation. Among them, small round steel of 5.5-25 mm is commonly used. Used as raw materials for manufacturing steel bars, bolts and various mechanical parts; hot-rolled round steel larger than 25 mm is mainly used for manufacturing mechanical parts or as raw materials for seamless steel pipe billets. [0003] The production steps of hot-rolled round steel mainly include molten iron smelting, alloy addition and deoxidation, slagging, casting and hot rolling. The general hot-rolled round steel has poor impact toughness during hot rolling due to the composition of molten steel in the refining p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/24C22C38/26C22C38/06C22C33/04C21C7/06C21D8/00
CPCC21C7/06C21D8/005C22C33/04C22C38/005C22C38/02C22C38/04C22C38/06C22C38/24C22C38/26Y02P10/20
Inventor 邹建国王忠伟袁子成
Owner TIANJIN RONGCHENG UNITED IRON & STEEL GRP CO LTD