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30CrMnSiNiA钢(炉号20T96)由700公斤上大下小戴帽口的圆锭锻成125方锻件,经900℃水淬后,纵向断面上出现了层状断口。自钢锭头部至尾部层状越来越严重,如照片1所示。这种层状断口的宏观特征是呈木层状断口,具有灰白色调的条带状或层状。机械性能试验表明,其纵向机械性能与正常纤维状断口的相同。而横向机械性能方面,尤其在塑性指标出现严重降低的现象。如表1所示,横向的面缩率仅达到这种钢规定值(≥25%)的一半。因此,这种层状断口应该属于一种低倍缺陷。
The 30CrMnSiNiA steel (furnace No. 20T96) was forged by a round ingot of 700 kg on a large cap and a small cap at 125 square forging. After being quenched at 900 ° C, a layered fracture appeared on the longitudinal section. From the ingot head to the tail layer more and more serious, as shown in Photo 1. The macroscopic feature of this layer-shaped fracture is a lamellar or lamellar, woody fracture. Mechanical tests show that the longitudinal mechanical properties of the same normal fibrous fracture. The transverse mechanical properties, especially in the plastic index serious decline phenomenon. As shown in Table 1, the lateral reduction is only half that of the steel specification (≥25%). Therefore, this layered fracture should belong to a low magnification defect.