低合金冷作模具钢中组织缺陷主要有:网状碳化物、碳化物呈带状偏析、碳化物液析。下面来详细讲讲相关内容吧。

The main structural defects in low alloy cold working die steel are network carbide, band segregation of carbide and liquid segregation of carbide. Let's talk about the relevant contents in detail.

1.现现网状碳化物，是由于钢材在轧制或锻造成形时，停轧或停锻温度较高而冷却速度过缓，二次碳化物沿奥氏体晶界呈网状析出，有时还会出现魏氏组织的碳化物，呈针状伸入晶内。

1. The present network carbides are due to the slow cooling rate due to the high stop rolling or stop forging temperature when the steel is rolled or forged. The secondary carbides are precipitated in a network along the austenite grain boundary, and sometimes the carbides of Widmanstatten structure may appear, which extend into the crystal in a needle shape.

2.碳化物呈带状偏析，是由于钢锭冷却时，微观结晶出现偏析，在树枝晶之间的后凝固区域，富集着碳和铬等溶质元素，凝固后析出聚集着大量碳化物，在锻轧过程中它逐步沿热加工方向延伸成带状。

2. The carbide is banded segregation, which is due to the segregation of the micro crystal during the cooling of the ingot. In the post solidification area between the dendrites, solute elements such as carbon and chromium are enriched. After solidification, a large number of carbides are precipitated and accumulated. During the forging and rolling process, it gradually extends into a band along the hot processing direction.

3.碳化物液析，是由于铸锭在冷却时会出现元素偏析，在后凝固区溶质含量高，形成碳及合金元素的富集区，当在晶界附近成分达到共晶成分时，凝固后会出现共晶莱氏体。这种亚稳定的共晶莱氏体在缓慢冷却的过程中，或在轧制加热时会形成离异共晶，离异出来的碳化物，经轧制后，呈白色多角状碎块沿轧制方向分布成链状或带状，常出现于钢材的中心地带。

3. Carbide liquidus is due to element segregation of ingot during cooling, high solute content in post solidification zone, forming enrichment zone of carbon and alloy elements. When the composition near the grain boundary reaches eutectic composition, eutectic ledeburite will appear after solidification. This metastable eutectic ledeburite will form divorced eutectic in the process of slow cooling or during rolling heating. After rolling, the separated carbides will be white polygonal fragments distributed in chains or bands along the rolling direction and often appear in the center of the steel.

此外低合金冷作模具钢中组织出现网状碳化物、碳化物呈带状偏析、碳化物液析等缺陷，导致模具在服役时出现工作面剥落、崩刃或开裂。也给模具的热处理带来不利的影响，往往会造成模具在淬火时出现淬裂。

In addition, the structure of low alloy cold working die steel has defects such as network carbide, band segregation of carbide and liquid segregation of carbide, which lead to the working surface peeling, edge collapse or cracking of the die during service. It also has an adverse effect on the heat treatment of the mold, often causing the mold to crack during quenching.

1.网状碳化物的方法，是采用正火处理

1. The method of eliminating network carbide is normalizing

2.碳化物呈带状偏析的方法，是对钢材重新进行合理锻造，锻造后控制冷却或锻造后淬火处理，热处理时再采用固溶双细化处理工艺。也可以根据偏析程度，直接采用固溶双细化处理工艺。

2. The method to eliminate the banded segregation of carbides is to re forge the steel reasonably, control the cooling after forging or quench after forging, and then adopt the solid solution double refining process during heat treatment. According to the degree of segregation, the solid solution double refining process can also be directly adopted.

3.碳化物液析的方法，是采用扩散退火处理，或固溶+急冷处理，或锻造后利用余热进行淬火处理。

3. The method to eliminate carbide precipitation is diffusion annealing treatment, solid solution + quenching treatment, or quenching treatment with residual heat after forging.

低合金冷作模具钢中组织缺陷相关内容就讲解到这里了，您可以关注我们网站https://www.jnqhmj.com咨询了解更多事项。

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