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| S30432超超临界锅炉管热变形内裂的研究与控制 |
| Research and Control of Hot Deformation Internal Crack of S30432 Ultra Supercritical Boiler Tube |
| Received:July 02, 2024 |
| DOI：10.3969/j.issn.1674-6457.2025.02.011 |
| 中文关键词: S30432 热穿孔 内裂 晶粒度 |
| 英文关键词: S30432 hot piercing internal crack grain size |
| 基金项目:国家自然科学基金(52005055);山西省重点研发计划(202102150401002);山西省专利转化项目(202403006) |
| Author Name | Affiliation | | WU Gui | Shanxi Tai Steel Stainless Steel Pipe Co., Ltd., Taiyuan 030003, China | | KANG Xitang | Shanxi Tai Steel Stainless Steel Pipe Co., Ltd., Taiyuan 030003, China | | LI Peng | Shanxi Tai Steel Stainless Steel Pipe Co., Ltd., Taiyuan 030003, China | | CHENG Yiming | Shanxi Tai Steel Stainless Steel Pipe Co., Ltd., Taiyuan 030003, China | | TUO Leifeng | School of Materials Science and Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, China | | CHU Zhibing | School of Materials Science and Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, China |
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| 中文摘要: |
| 目的 针对S30432在热变形过程中的内裂问题，研究不同坯料晶粒度对热轧荒管纵向内裂的影响，以及不同原料在相同热轧变形工艺下热轧荒管纵向内裂的原因，找出解决热变形内裂的方法。方法 利用金相显微镜、二次电子扫描(SEM)以及能量色散X射线检测器(EDX)等手段进行组织与化学分析，分别研究不同晶粒度的圆钢以及不同加热工艺对热穿孔内裂的影响。结果 在穿孔温度为1 100~1 170 ℃条件下，随着固溶温度的升高，试样硬度逐渐下降，屈服强度与抗拉强度也呈现下降趋势，其下降速率小于硬度下降速率，当穿孔温度为1 150~1 170 ℃时，硬度下降速度最快;屈服强度与抗拉强度也呈现下降趋势，其下降速率小于硬度下降速率，与1#圆钢相比，2#圆钢的抗拉强度下降较大;当穿孔温度为1 100~1 170 ℃时，随着热变形温度的升高，当原料晶粒度为7~8级时，穿孔后钢管的内壁无内裂现象，变形后的晶粒度在8.5~7级且级差较小;当原料晶粒度为4~6级时，穿孔后钢管内壁出现内裂，1 170 ℃热变形后的晶粒度在8~3级且级差较大。结论 S30432钢管热变形内裂的主要原因为沿变形方向出现大量含Nb析出物，造成局部成分偏析，降低了晶界的结合力，热穿孔变形时内壁受到拉压两向应力作用，进一步引起内表面开裂，当控制原料晶粒度为7~8级、加热温度为1 110~ 1 170 ℃时，可以有效控制热变形过程中荒管的纵向内裂。 |
| 英文摘要: |
| The work aims to study the effect of different grain size on the longitudinal internal cracking of hot-rolled barren tubes, explore the causes of longitudinal internal cracking of hot rolled tubes with different raw materials under the same hot rolling deformation process, and find out the method of solving the internal cracking of thermal deformation of S30432. Using metallographic microscope, secondary electron scanning (SEM), energy scattered X-ray detector (EDX) and other methods for microstructure and chemical analysis, the effects of different grain sizes of round steel and different heating processes on internal cracking of hot perforation were studied. As a result, at the piercing temperature of 1 100 to 1 170 ℃, as the solid solution temperature increased, the hardness of the sample gradually decreased, and the yield strength and tensile strength also showed a downward trend. Its decrease rate was less than that of the hardness. The hardness decreased the fastest when solid solution at 1 150-1 170 ℃; The yield strength and tensile strength also shows a downward trend. Its decrease rate was less than that of the hardness. Compared with 1# sample, the tensile strength of 2# sample decreased greatly. At piercing temperature of 1 100 to 1 170 ℃, as the thermal deformation temperature rose, the granular grain size of the raw material was free from internal cracking in the inner wall of the steel pipe after the perforation between 7-8 levels. The grain size after deformation was 8.5-7 and the difference was small. When the grain size of the raw material was 4-6, the inner wall of the steel tube after perforation had internal cracks, and the grain size after hot deformation at 1 170 ℃ was 8-3 and the difference was large. In conclusion, the main reason for thermal deformation internal cracking is that a large number of Nb-containing objects in the direction of the deformation causes local component bias, which reduces the binding force of the crystal world. The inner wall is severely cracked when it is stretched. When the granularity of the raw material is between level 7-8 and the heating temperature is between 1 110-1 170 ℃, it can effectively control the vertical internal cracks of the deformation process during the thermal deformation. |
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