低温钢9Ni钢的最低使用温度为( )A. -40B. -70C. -100D. -196

一蓄水铁箱上被腐蚀了一个洞，今用一金属片焊接在洞外面以堵漏，为了延长铁箱的寿命，选用哪种金属片为好?()A. 铜片B. 铁片C. 锌片D. 镀锡铁片

一合金之成分为90Pb-10Sn。(a)请问此合金在100℃、200℃、300℃时含有哪几种相?(b)在哪个温度围将只有一相存在?(参看图4-9)Composition of an alloy is 90Pb-10Sn. (a) Which phases is contained at 100℃, 200℃, 300℃? (b) In which temperature range will be only one phase exists? (See Figure 4-9).答:(a)成分为90Pb-10Sn的合金对应的为红色的垂直线,分别在100℃、200℃、300℃作水平线得到交点a,b,c,所以100℃时,交点a位于α+β相区,所以有α和β两相。200℃时,交点b位于α单相区,所有只有α一相。300℃时,交点c位于液相线上,此为两相共存线,所以有液相L和α两相。( )A. Composition of alloy is 90Pb-10Sn alloy which corresponding to the red vertical line, it intersect with the temperature level line at a, B. and C. points. So, there are two phases at 100℃, α and β; there is only one phase at 200℃, α; point c lies on the liquidus line, so there are two phases at 300℃, L and α. D. f, then draw horizontal lines to get the corresponding temperature. So when the temperature is more than 300℃, liquid phase L exists. When the temperature is between 148 ~ 268℃, there is only α p E. and F. G. et three points, d, e and f, then draw horizontal lines to get the corresponding temperature. So when the temperature is more than 300℃, liquid phase L exists. When the temperature is between 148 ~ 268℃, there is only α phase.

母材强度等级越高,软化问题越严重。A. 正确B. 错误

测量拉伸力直至材料断裂为止,所承受的最大拉伸应力称为拉伸强度。A. 正确B. 错误

13/15(分值4.0分,难度:中)油漆说明书提供了理论涂布率,但由于使用过程中不可避免的浪费,因此实际涂布率肯定会理论涂布率要____小。A. 错误B. 正确

在生产中,习惯把淬火和高温回火相结合的热处理方法称为预备热处理 (调质处理 )。A. 正确B. 错误

在筛板上，联络索穿过筛孔时，包在联络索外面的物质是（ ）。A. 侵填体B. 胼胝质C. 胼胝体D. 树脂

()低温压力容器用钢 16MnDR 的最低使用温度为 -20 °C。A. 正确B. 错误

中碳调质钢热影响区产生严重脆化使其淬硬倾向大，产生大量高碳马氏体所致。常用的防止措施是采用大的热输入配合预热、缓冷及后热等措施。()A. 对B. 错