B＋级钢壁厚对力学性能影响的研究

Study on Effects of B^＋ Steel Wall Thickness to Mechanical Properties

以铁路货车转向架主要铸件的材质B^＋级钢为研究对象，通过对不同壁厚B^＋级钢铸件进行标准拉伸、冲击试验，研究铸件壁厚变化对其力学性能的影响。结果发现B^＋级钢壁厚在14～50mm区间内，随着壁厚增加，铸造试块边缘的抗拉强度和冲击性能有缓慢增加的趋势，但并不明显；随着壁厚继续增加，铸造试块中心的抗拉强度和冲击性能明显降低，当壁厚达到50mm时，抗拉强度和冲击性能只有其对应边缘部位的30％左右。

The B^＋ grade steel for the railway freight car bogie was taken as the study object. By the test for B^＋ steel casting with different wall thickness, the effects of its changing on mechanical properties were studied. The test results show that the tensile strength and impact performance at the edge become slowly higher with the increasing of the wall thickness in range of 14-50 mm, and the mechanical properties in the center decrease obriously with the wall thickness to 50 mm, and only 30% of the edge.