High-strength steel plate with yield strength at 690MPa level and manufacture method thereof

A yield strength, 690mpa technology, applied in the field of high-strength steel plate and its manufacturing, can solve the problems of increasing the difficulty of smelting and continuous casting, deteriorating welding performance, increasing carbon content, etc., to reduce C content, reduce alloy costs, and reduce process costs. Effect

Inactive Publication Date: 2013-01-23
INNER MONGOLIA BAOTOU STEEL UNION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Chinese patent CN1218115 discloses "copper-boron low-carbon and ultra-low-carbon bainite high-strength steel". And other elements promote bainite phase transformation, and at the same time use ε-Cu and Nb, Ti composite precipitation to obtain high strength; the disadvantage is that the addition of Cu element increases the difficulty of smelting and continuous casting
It is on the basis of ordinary low-carbon micro-alloy steel, by properly adjusting the C content in the steel and matching with reasonable technological means, the yield strength of the simple composition system micro-alloy steel can reach 800MPa; the disadvantage is that the carbon content is increased , which deteriorates solderability
The disadvantage is that the strength is 550MPa level

Method used

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  • High-strength steel plate with yield strength at 690MPa level and manufacture method thereof
  • High-strength steel plate with yield strength at 690MPa level and manufacture method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Smelted according to the chemical composition shown in Table 1, and cast into steel ingots, the steel ingots were heated to 1220 ° C, kept for 150 minutes, and the first stage of rolling was carried out on the experimental rolling mill, that is, rolling in the austenite recrystallization zone. 1170°C, the first to second pass reduction should be greater than 10%, followed by at least 1 to 2 pass reduction rate controlled at 20 to 40%, when the thickness of the rolled piece is 60mm, wait for the temperature on the roller table to 900 ° C, followed by the second stage of rolling, that is, rolling in the austenite non-recrystallized zone. The final rolling temperature is 840°C, and the thickness of the finished steel plate is 20mm. After rolling, the steel plate enters the accelerated cooling (ACC) device and is cooled to 400°C at a rate of 25°C / s, and the cooling bed is cooled after the water exits. Afterwards, the steel plate is subjected to tempering heat treatment, th...

Embodiment 2

[0034] The embodiment is the same as in Example 1, wherein the heating temperature is 1200° C., and the heat preservation is 150 minutes. The rolling start temperature of the first stage rolling is 1160° C., the thickness of the rolled piece is 54 mm, and the rolling start temperature of the second stage rolling is 910° C. The final rolling temperature is 830°C, the thickness of the finished steel plate is 18mm; the cooling rate of the steel plate is 25°C / s, and the final cooling temperature is 400°C. Afterwards, the steel plate is subjected to tempering heat treatment, the tempering temperature is 480°C, and the holding time is 20min+t×2.5min / mm, where t is the thickness of the steel plate in mm.

Embodiment 3

[0036] The implementation is the same as in Example 1, wherein the heating temperature is 1200° C., and the heat preservation is 150 minutes; the rolling start temperature of the first stage rolling is 1150° C., and the thickness of the rolled piece is 48 mm; the rolling start temperature of the second stage rolling is 910° C., The final rolling temperature is 840°C, the thickness of the finished steel plate is 16mm; the cooling rate of the steel plate is 27°C / s, and the final cooling temperature is 380°C. Afterwards, the steel plate is subjected to tempering heat treatment, the tempering temperature is 480°C, and the holding time is 20min+t×2.5min / mm, where t is the thickness of the steel plate in mm.

[0037] Table 1 Chemical composition (wt %) of embodiment 1~3 of the present invention

[0038] Example

C

Si

mn

P

S

Cr

Mo

B

Nb

V

Ti

1

0.078

0.25

1.70

0.007

0.007

0.38 ...

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Abstract

The invention provides a high-strength steel plate with yield strength at 690MPa level and a manufacture method of the high-strength steel plate, and belongs to the field of low-alloy high-strength steel. The steel plate comprises the following chemical components in percentage by weight: 0.04-0.09% of C, 0.25-0.50% of Si, 1.4-1.7% of Mn, not greater than 0.020% of P, not greater than 0.010% of S, not greater than 0.45% of Cr, not greater than 0.20% of Mo, 0.04-0.05% of Nb, 0.05-0.07% of V, 0.005-0.020% of Ti, 0.0005-0.0025% of B, and the balance of Fe and inevitable impurities. According to the high-strength steel plate with yield strength at 690MPa level and the manufacture method provided by the invention, the low-carbon microalloying design is adopted, the technology in combination of TMCP (Thermal Mechanical Control Processing) and tempering is carried out, so that a matrix structure with fine Bainite as the major is obtained, and as a result, the strength, the plasticity and the toughness are in good match. The high-strength steel plate with yield strength at 690MPa level and the manufacture method can be widely applied to the fields such as the engineering machinery field and the coal mine machinery field.

Description

technical field [0001] The invention belongs to the field of low-alloy high-strength steel, in particular to a high-strength steel plate with a yield strength of 690 MPa and a manufacturing method thereof. Background technique [0002] It is generally believed that a steel plate with a yield strength greater than 345MPa is called a high-strength steel plate. With the development of construction machinery and coal mining machinery in the direction of large-scale equipment, light weight, and heavy load, the amount of high-strength steel plates is increasing, and the strength level is also increasing rapidly. Traditional high-strength steel plates for construction machinery are mainly solid solution Strengthening and precipitation strengthening are mainly used to increase the strength, in which the content of carbon and alloy elements is relatively high, and most of them are quenched and tempered. Different degrees of pre-weld preheating and post-weld heat treatment are requir...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/38C22C38/32C22C38/14C21D8/02C21D1/18
Inventor 杨雄史文义袁晓鸣王海明张辉路璐任丽芳程德富
Owner INNER MONGOLIA BAOTOU STEEL UNION
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