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一 是非题 1 正火中碳钢截面积相等的圆形与矩形两种试样拉伸,圆形试样的δ、ψ测定值较高。( ) 2 HV测定,为提高准确度应尽量选大载荷。( ) 3 因规定伸长率同为0.2％,故生产检验可用方便的δ_(r0.2)验证试验来代替费时的δ_(p0.2)测定。( ) 4 裂纹扩展功(A_p)比裂纹形成与扩展总功(A_k)更适于作为材料的韧性指标。( ) 5 某一Cu合金与某一Al合金的硬度值同为51HSD,应当认为两者的硬度相同。( ) 6 冲击载荷下材料的塑变抗力提高,脆性倾向减小。( ) 7 冶金质量检验常采用U型试样进行常温冲击试验,因钢铁的韧脆转变温度在常温范围。( ) 8 当材料强度水平高,增大韧性,反而降低材料多冲抗力。( ) 9 三点弯曲试验,一般来说试样总是在施加载荷F的地方破坏。( ) 10 圆柱形试样进行扭转加载时,试样沿长度的塑性变形因材料而异,有局部变形和均匀变形两种形式。( )
First, non-problem 1 normalizing carbon steel cross-sectional area of equal circular and rectangular specimens of two tensile, circular specimen δ, ψ measured higher. () 2 HV measurement, to increase the accuracy should try to choose a large load. () 3 Because of the same elongation of 0.2%, the production test can be replaced by the time-consuming δ_ (p0.2) test with a convenient δ_ (r0.2) verification test. (4) The crack extension work (A_p) is more suitable as a toughness index for the material than the crack growth and extension work (A_k). () 5 The hardness of a certain Cu alloy is the same as that of a certain Al alloy, and the hardness of both alloys should be considered the same. () 6 The plastic deformation resistance of the material under impact load increases, and the tendency of brittleness decreases. () 7 Metallurgical Quality Inspection U-shaped samples are often used at room temperature impact test, due to the ductile-brittle transition temperature of steel at room temperature range. () 8 When the material strength level is high, increase the toughness, but reduce the material more resistance. () 9 three-point bending test, in general, the sample is always damaged in the place where the load F is applied. () 10 cylindrical specimens for torsional loading, the sample along the length of the plastic deformation of different materials, there are two forms of local deformation and uniform deformation. ()