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A low-cost q355c steel plate production process

A production process and low-cost technology, applied in the field of steel plates, can solve problems such as difficult to achieve low-cost production and high prices, and achieve the effect of improving 0°C impact toughness and compensating for strength loss

Active Publication Date: 2021-07-20
TIANJIN IRON & STEEL GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because of the requirement of impact toughness at lower temperatures, microalloying elements such as Nb and V are routinely used for microalloying in production to ensure the strength of the steel plate and obtain good toughness at the same time, but the price of microalloying elements such as Nb and V Expensive, difficult to achieve low-cost production

Method used

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  • A low-cost q355c steel plate production process
  • A low-cost q355c steel plate production process
  • A low-cost q355c steel plate production process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Steel species: Q355C; 2. 20 mm thickness thickness; rolled product specification: 16mm; quantity: 8 pieces, total 80.20t.

[0035] 1, smelting component: C = 0.17%, Si = 0.30%, Mn = 1.45%, P = 0.015%, S = 0.012%, Alt = 0.025%;

[0036] The slab is low, H content is 2.5 ppm, t [o]: 20 ppm; N content 44 ppm.

[0037] 2, average heat temperature: 1200 ° C; rough rolling temperature: 1130 ° C; finished rolling temperature: 950 ° C; final rolling temperature 840 ° C; ACC finishing temperature 680 ° C.

[0038] 3, the crude rolling channel is assigned to 7 / 7, the intermediate blank 80mm, the intermediate blank is compressed ratio 5, and the specific parameters are shown in Table 1.

[0039] Table 1 Example 1 Scene of rolling channel

[0040]

[0041] 4, the steel sheet is rolled down the line to pile up, the lower line temperature is 250 ° C.

[0042] 5, the steel sheet is piled up to the room temperature and then dismantled automatic flaw, the detection standard is GB / T 2970...

Embodiment 2

[0047] Steel species: Q355C; 2. 20mm thickness thickness; rolled product specification: 30mm; quantity: 7, a total of 85.23t.

[0048]1, smelting component: C = 0.15%, Si = 0.35%, Mn = 1.51%, P = 0.018%, S = 0.010%, Alt = 0.025%;

[0049] The slab is low, the H content is 2.5 ppm, T [o]: 22 ppm; N content 49 ppm.

[0050] 2, average heat temperature: 1180 ° C; rough rolled rolling temperature: 1100 ° C; finishing rolling temperature: 910 ° C; final rolling temperature 840 ° C; ACC finishing at 10 ° C.

[0051] 3, the crude rolling channel is assigned to 7 / 7, the intermediate blank is 110mm, the intermediate blank is compressed ratio 3.7, and the specific parameters are shown in Table 3.

[0052] Table 3 Example 2 Rolling Channel

[0053]

[0054] 4, the steel sheet is rolled off the line to the lower line, the lower line temperature is 280 ° C.

[0055] 5, the steel sheet is piled up to the room temperature and then dismantled automatic flaw, the detection standard is GB / T 297...

Embodiment 3

[0060] Steel species: Q355C; 2. 200 mm thickness of the die; rolled finished product specification: 50mm; quantity: 6 pieces, total 78.72t.

[0061] 1, smelting component: C = 0.18%, Si = 0.32%, Mn = 1.56%, P = 0.017%, S = 0.008%, Alt = 0.030%;

[0062] The slab is low, H content 1.8 ppm, T [o]: 20 ppm; N content 46 ppm.

[0063] 2, average heat temperature: 1160 ° C; rough rolling, rolling temperature: 1090 ° C; finishing rolling temperature: 870 ° C; final rolling temperature 850 ° C; ACC refrigeration temperature 630 ° C.

[0064] 3, the coarse rolling channel is assigned to 5 / 7, the intermediate blank is 150mm, the intermediate blank compression ratio 3, and the specific parameters are shown in Table 5.

[0065] Table 5 Example 3 Rolling Channel

[0066]

[0067] 4, the steel plate rolling is lowered, and the line is piled up, the lower line temperature is 310 ° C.

[0068] 5, the steel sheet is piled up to the room temperature and then dismantled automatic flaw, the detecti...

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Abstract

The invention relates to a low-cost Q355C steel plate production process. The chemical composition according to mass percentage is as follows: C: 0.11%-0.20%, Si: ≤0.20-0.45%, Mn: 1.1%-1.6%, Alt: 0.015%-0.045% , P: ≤0.025%, S: ≤0.015%, the rest is Fe; through converter smelting, reasonable end-point carbon content control, complete deoxidation, white slag refining and soft blowing, calcium treatment at the same time, and continuous casting to improve the internal quality of the steel plate ;Through the two-stage controlled rolling of rough and finish rolling, the rolling temperature, speed and pass are reasonably distributed to further improve the internal quality of the steel plate. The invention reduces the C content, improves the impact toughness at 0°C, and replaces expensive Nb and V with cheap micro-alloying elements Al to maximize profits, and further improves the impact toughness at the same time, and produces Q355C steel plates through a rolling process that matches the composition. Ton of steel can be reduced by 50 yuan.

Description

Technical field [0001] The present invention belongs to the technical field of steel sheets, in particular, to a low-cost Q355C steel production process. Background technique [0002] The Q345 level low alloy structural steel is one of the most basic steels. There is a large amount of maintenance and circulation in the market, and the standards of its implementation are GB / T 1591-2008, the standard is on February 1, 2019 The new version of GB / T 1591-2018 is replaced. The new standard is the largest level of Q345 intensity level. In the new version, the Q345 level number is canceled, replaced with Q355 grades, and the intensity level performance requires the international standard ISO and the European standard EN phase, will yield 345MPa The requirements are changed to yield 355MPa. Therefore, the market is facing a situation of transition from Q345 to Q355. [0003] Q355C steel belongs to a high-quality low alloy structural steel, compared to normal quality level Q355B, P, S ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/06C21D8/02
CPCC21D8/0226C22C38/02C22C38/04C22C38/06
Inventor 王佩鑫刘桂华张楠计艳辉徐振坤
Owner TIANJIN IRON & STEEL GRP
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