800MPa-grade steel for ships and preparation method of 800MPa-grade steel

A technology for marine use and impurities, which is applied in the field of marine steel and its preparation, and achieves the effects of good low temperature toughness, fine structure and grain, and excellent crack arrest performance.

Active Publication Date: 2016-12-07
SHOUGANG CORPORATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a 800MPa grade ship steel and its preparation method, which solves th

Method used

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  • 800MPa-grade steel for ships and preparation method of 800MPa-grade steel

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0017] Example 1

[0018] The weight percentage of the chemical composition of the steel billet includes: C: 0.081%, Si: 0.22%, Mn: 0.84%, P: 0.007%, S: 0.0041%, B: 0.001%, Ni: 4.78%, Cr: 0.74%, Mo: 0.62%, V: 0.050%, the rest is Fe and unavoidable impurities.

[0019] 1. Smelting and forging: use 500Kg vacuum smelting furnace to make steel, and forge into 175mm billet after casting;

[0020] 2. Heating system: heating to 1200°C, holding for 3h;

[0021] 3. Rolling process: the rolling process is divided into two stages, rolling in the recrystallized zone and rolling in the unrecrystallized zone: the rolling start temperature in the recrystallized zone is 1087℃, and a total of 4 passes are rolled to the middle billet The thickness to be heated is 60mm; when the temperature reaches 870°C, the rolling is performed in the non-recrystallization zone, and the final rolling temperature is 817°C. A total of 5 passes are rolled to the target thickness of 20mm;

[0022] 4. Cooling process after...

Example Embodiment

[0025] Example 2

[0026] The chemical composition of the steel billet includes, by weight percentage, C: 0.078%, Si: 0.21%, Mn: 0.69%, P: 0.007%, S: 0.0041%, B: 0.0006%, Ni: 4.5%, Cr: 0.667%, Mo: 0.527%, V: 0.043%, the rest is Fe and unavoidable impurities.

[0027] The smelting, forging, and heating system are the same as in Example 1.

[0028] Rolling process: The rolling process is divided into two stages, rolling in the recrystallized zone and rolling in the non-recrystallized zone: the rolling start temperature in the recrystallized zone is 1057℃, and a total of 4 passes are rolled until the intermediate billet is heated The thickness is 60mm; when the temperature reaches 860℃, the rolling is carried out in the non-recrystallized zone, the final rolling temperature is 810℃, and a total of 5 passes are rolled to the target thickness of 20mm;

[0029] Cooling process after rolling: water cooling to 450℃ after rolling, cooling rate 12℃ / s, then air cooling to room temperature;

[00...

Example Embodiment

[0032] Example 3

[0033] The chemical composition of the steel billet includes C: 0.076%, Si: 0.20%, Mn: 0.83%, P: 0.007%, S: 0.0044%, B: 0.0003%, Ni: 4.83%, Cr: 0.73%, Mo: 0.521%, V: 0.039%, and the rest is Fe and unavoidable impurities.

[0034] The smelting, forging, and heating system are the same as in Example 1;

[0035] Rolling process: The rolling process is divided into two stages, rolling in the recrystallized zone and rolling in the non-recrystallized zone: the rolling start temperature in the recrystallized zone is 1050℃, and a total of 3 passes are rolled until the intermediate billet is warmed. The thickness is 85mm; the non-recrystallized zone is rolled after the temperature reaches 850°C, and the final rolling temperature is 820°C. A total of 3 passes are rolled to the target thickness of 40mm;

[0036] Cooling process after rolling: air cooling to room temperature after rolling;

[0037] Heat treatment process: the quenching temperature is 910℃ for 100min and then wa...

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Abstract

The invention discloses 800MPa-grade steel for ships and a preparation method of the 800MPa-grade steel, and belongs to the technical field of steel and iron materials. The 800MPa-grade steel for ships comprises, by weight, 0.05-0.10% of C, 0.10-0.25% of Si, 0.20-1.0% of Mn, less than or equal to 0.015% of P, less than or equal to 0.010% of S, less than or equal to 0.0015% of B, 3.5-5.5% of Ni, 0.3-0.9% of Cr, 0.2-0.7% of Mo and the like. The steel is smelted with a converter; then the steel is heated to 1150-1200 DEG C, and heat preservation is carried out for 2.5-3.5 hours; the steel is rolled in a recrystallization area and a non-recrystallization area; then air cooling is carried out; and finally the steel is subjected to quenching thermal treatment, and the quenching temperature is 880-930 DEG C. The 800MPa-grade steel for ships has the advantages of high strength, good plasticity and excellent crack arresting performance.

Description

technical field [0001] The invention belongs to the technical field of iron and steel materials, and in particular relates to an 800MPa grade ship steel and a preparation method thereof. In particular, it relates to a ship steel with 800MPa grade NDTT lower than -80°C and a preparation method thereof. Background technique [0002] With the development of the shipbuilding industry, the requirements for the strength, toughness, weldability and surface quality of steel materials for ships are constantly increasing. Especially for the 10,000-ton ships in the far sea navigation area, in order to reduce the dead weight and increase the load, the hull needs to use high-strength steel plates; at the same time, in order to ensure the safety and reliability of the ship, the ship plate is required to have good toughness in the low temperature service environment and lower NDT temperature. [0003] At present, the production methods of high-strength steel with yield strength higher th...

Claims

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Application Information

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IPC IPC(8): C22C38/08C22C38/02C22C38/04C22C38/32C22C38/18C22C38/12C21D8/02C21D1/25C21D6/00
CPCC21D1/25C21D6/001C21D8/0226C21D8/0247C22C38/02C22C38/04C22C38/08C22C38/12C22C38/18C22C38/32
Inventor 黄乐庆狄国标麻庆申王彦锋杨永达刘美艳马长文隋鹤龙王小勇韩承良杨春卫黄少帅汤海芳
Owner SHOUGANG CORPORATION
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