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。
The main structural defects in low alloy cold working die steel are network carbide, banded carbide segregation and carbide liquid segregation.
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 reticular carbide is due to the high temperature of stopping rolling or stopping forging and the slow cooling rate during rolling or forging. The secondary carbides precipitate in network along the austenite grain boundary, and sometimes there are carbides with widmanstatten structure, which extend into the crystal in 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 reason for the banded segregation of carbides is that when the ingot is cooled, the micro crystallization segregation occurs. In the final solidification area between the dendrites, there are solute elements such as carbon and chromium. After solidification, a large number of carbides are precipitated and accumulated. During the forging and rolling process, it gradually extends along the hot working direction into a strip.
③ 碳化物液析，是由于铸锭在冷却时会出现元素偏析，在凝固区溶质含量高，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 the element segregation when the ingot is cooled. The solute content in the final solidification zone is high, forming the enrichment zone of carbon and alloy elements. When the composition near the grain boundary reaches the eutectic composition, eutectic ledeburite will appear after solidification. The metastable eutectic ledeburite will form divorced eutectic in the process of slow cooling or heating during rolling. After rolling, the separated carbides are white polygonal, and the fragments are distributed in chain or strip along the rolling direction, which often appear in the center of the steel.
The main structural defects in low alloy cold working die steel are network carbide, banded carbide segregation and carbide liquid segregation.
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 reticular carbide is due to the high temperature of stopping rolling or stopping forging and the slow cooling rate during rolling or forging. The secondary carbides precipitate in network along the austenite grain boundary, and sometimes there are carbides with widmanstatten structure, which extend into the crystal in 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 reason for the banded segregation of carbides is that when the ingot is cooled, the micro crystallization segregation occurs. In the final solidification area between the dendrites, there are solute elements such as carbon and chromium. After solidification, a large number of carbides are precipitated and accumulated. During the forging and rolling process, it gradually extends along the hot working direction into a strip.
③ 碳化物液析，是由于铸锭在冷却时会出现元素偏析，在凝固区溶质含量高，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 the element segregation when the ingot is cooled. The solute content in the final solidification zone is high, forming the enrichment zone of carbon and alloy elements. When the composition near the grain boundary reaches the eutectic composition, eutectic ledeburite will appear after solidification. The metastable eutectic ledeburite will form divorced eutectic in the process of slow cooling or heating during rolling. After rolling, the separated carbides are white polygonal, and the fragments are distributed in chain or strip along the rolling direction, which often appear in the center of the steel.
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