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Manufacturing method of medium-carbon CrMo steel wire rod free of annealing and drawing

A manufacturing method, an annealing-free technology, applied in the direction of temperature control, metal rolling, etc., can solve the problems of high mechanical performance requirements for uniform cleaning rods, failure to meet the rolling temperature requirements in the two-phase region, and coarse pearlite grains. , to avoid the formation of abnormal tissue in the center, improve the internal quality and reduce the strength

Active Publication Date: 2019-07-12
JIANGYIN XINGCHENG GOLD MATERIALS CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The CN102676929A invention patent ignores the importance of rolling, and the example describes that the final rolling temperature is above 820°C, which does not meet the temperature requirements for rolling in the two-phase region, resulting in coarse pearlite grains with different sizes and ferrite The content is very low; direct drawing or cold heading without annealing requires higher requirements on the uniformity of the structure (the center should not have abnormal martensite structure, the overall grain should be fine and uniform) and the mechanical properties of the rod

Method used

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  • Manufacturing method of medium-carbon CrMo steel wire rod free of annealing and drawing
  • Manufacturing method of medium-carbon CrMo steel wire rod free of annealing and drawing
  • Manufacturing method of medium-carbon CrMo steel wire rod free of annealing and drawing

Examples

Experimental program
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Effect test

Embodiment 1

[0030] The specifications of the non-annealing medium carbon CrMo steel wire rod involved in this example are φ14mm, and the contained components and their mass percentages are: C: 0.36%, Si: 0.18%, Mn: 0.70%, P: 0.010%, S: 0.003 %, Cr: 1.06%, Mo: 0.17%, Al: 0.025%, N: 0.0056%, O: 0.0008%, H: 0.0001%, and the balance is iron and unavoidable impurity elements.

[0031] The production process of this annealing-free medium carbon CrMo steel wire rod is as follows:

[0032] The smelting raw materials are configured according to the chemical composition of the wire rod, followed by KR molten iron pretreatment-converter smelting-LF+RH refining-continuous casting-continuous casting slab warm or hot delivery-continuous casting slab heating, billet opening-intermediate billet surface cleaning - Reheating - Descaling with high pressure water - Controlled rolling and temperature control - Controlled cooling - Wire rod.

[0033] In the KR hot metal pretreatment, the molten iron is desulf...

Embodiment 2

[0039] The specifications of the non-annealing medium carbon CrMo steel wire rod involved in this embodiment are φ5.5mm, and the components and their mass percentages are: C: 0.35%, Si: 0.18%, Mn: 0.69%, P: 0.0012%, S : 0.003%, Cr: 1.05%, Mo: 0.17%, Al: 0.028%, N: 0.0055%, O: 0.0008%, H: 0.0001%, and the balance is iron and unavoidable impurity elements.

[0040] The production process of wire rod is basically the same as Example 1, but there are differences in its rolling and cooling process, as follows:

[0041] The continuous casting billet is opened to obtain the intermediate billet (140mm 2 ), heating stage I at 800°C, heating stage II at 980-1010°C, heating stage III at 1025°C, heating stage III holding time for 45 minutes, total heating time of 100 minutes, residual oxygen in the furnace: 0.9%, and descaling with high-pressure water after leaving the furnace , and then rolled. The rough rolling start temperature is 900℃, the total compression ratio is 68%; the finishi...

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Abstract

The invention relates to a manufacturing method of a medium-carbon CrMo steel wire rod free of annealing and drawing, and belongs to the field of wire rod production. Raw materials are prepared and smelted according to chemical compositions, and KR hot metal pretreatment, converter smelting, LF and RH refining, steel blank machining, warm supply or heat supply, steel blank heating and cogging, middle blank surface clearing, reheating, high-pressure water descaling, rolling control and temperature control, cooling control and wire rod forming are carried out in sequence. Rolling comprises roughrolling, medium finish rolling and reducing and sizing. In the medium finish rolling process, in the later period, rolled parts are subjected to water cooling to be below phase change temperature, and the compression ratio of the last two passes is set to be larger than or equal to 35%; coils are slowly cooled online; and the roller speed is constant, a heat preservation cover is closed for heatpreservation, and the rolled parts are discharged out of the cover to be subjected to air cooling to room temperature. The wire rod needs no annealing before drawing, large-draft drawing can be directly carried out, the production cost is reduced, and energy saving and environment protection are achieved.

Description

technical field [0001] The invention relates to the field of wire rod steel metallurgical production, in particular to a method for manufacturing a medium-carbon CrMo steel wire rod without drawing and annealing. Background technique [0002] As we all know, the annealing heat treatment cycle is long, the energy consumption is large, and the cost is high. At present, the country is vigorously calling for energy conservation and environmental protection. How to realize direct drawing without annealing is a common problem faced by domestic steel mills, and it is also the key to enhancing the competitiveness of the industry. [0003] The organic combination of thermal deformation and phase transformation of materials can improve the microstructure and mechanical properties of materials without subsequent heat treatment. The outstanding advantages of controlled rolling and controlled cooling have prompted various domestic manufacturers to actively practice. However, due to the h...

Claims

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Application Information

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IPC IPC(8): C22C38/22C22C38/06C22C38/04C22C38/02C21C1/02C21C7/068C21C7/064C21C7/10B22D11/18C21D8/02B21B1/16B21B37/74
CPCB21B1/16B21B37/74B22D11/18C21C1/02C21C7/064C21C7/068C21C7/10C21D8/0205C21D8/0226C21D2211/005C21D2211/009C22C38/001C22C38/002C22C38/02C22C38/04C22C38/06C22C38/22
Inventor 王海华张剑锋林再勇何佳锋陈金伟
Owner JIANGYIN XINGCHENG GOLD MATERIALS CO LTD
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