(1)淬透性低。一般情况下，碳钢水淬的大淬透直径只有10mm-20mm。

(1) low hardenability. Under normal circumstances, the quenching temperature of carbon steel is only 10mm-20mm.

(2)强度和屈强比较低。如普通碳钢Q235钢的σs为235MPa，而低合金结构钢16Mn的σs则为360MPa以上。40钢的σs/σb仅为0.43,远低于合金钢。

(2) strength and yield strength are relatively low. Such as ordinary carbon steel Q235 steel. S is 235MPa, and low alloy structural steel 16Mn is above 360MPa. S. 40 sigma Sigma s/ steel B was only 0.43, far lower than that of alloy steel.

(3)回火稳定性差。由于回火稳定性差，碳钢在进行调质处理时，为了保证较高的强度需采用较低的回火温度，这样钢的韧性就偏低；为了保证较好的韧性，采用高的回火温度时强度又偏低，所以碳钢的综合机械性能水平不高。

(3) poor tempering stability. Due to poor stability of carbon steel in tempering, quenching and tempering treatment, in order to ensure the high strength with the tempering temperature is lower, so the toughness of the steel is lower; in order to ensure good toughness, with high tempering temperature strength and low carbon steel, so the comprehensive mechanical performance level is not high.

(4)不能满足特殊性能的要求。碳钢在抗氧化、耐蚀、耐热、耐低温、耐磨损以及特殊电磁性等方面往往较差，不能满足特殊使用性能的需求。

(4) can not meet the requirements of special performance. Carbon steels are often poor in oxidation resistance, corrosion resistance, heat resistance, low temperature resistance, wear resistance and special electromagnetic properties, which can not meet the needs of special service performance.