铸铁与铁钢的阀门主要区别是含碳量不同，含碳量直接影响钢材的强度、塑性。碳钢也叫碳素钢，含炭量WC小于2%的铁碳合金。碳钢除含碳外一般还含有少量的硅、锰、硫、磷 按用途可以把碳钢分为碳素结构钢、碳素工具钢和易切削结构钢三类。碳素结构钢又分为建筑结构钢和机器制造结构钢两种 按含碳量可以把碳钢分为低碳钢（WC ≤ 0.25%）,中碳钢（WC0.25%——0.6%）和高碳钢（WC>0。6%） 按磷、硫含量可以把碳素钢分为普通碳素钢（含磷、硫较高）、优质碳素钢（含磷、硫较低）和高级优质钢（含磷、硫更低） 一般碳钢中含碳量较高则硬度越高，强度也越高，但塑性较低。
The main difference between iron and steel valves is the carbon content, which directly affects the strength and plasticity of steel. Carbon steel, also known as carbon steel, contains less than 2% WC iron-carbon alloy. In addition to carbon, carbon steel generally contains a small amount of silicon, www.baodingbanjia56.com tuogun.07858.net www.weishengzhiji.cn www.bdxn.net www.qibiji58.com www.suolijc.commanganese, sulphur and phosphorus. According to its use, carbon steel can be divided into three categories: carbon structural steel, carbon tool steel and free cutting structural steel. Carbon structural steels are divided into building structural steels and machine-made structural steels. According to the carbon content, carbon steels can be divided into low carbon steels (WC < 0.25%), medium carbon steels (WC 0.25% - 0.6%) and high carbon steels (WC > 0). 6% According to the content of phosphorus and sulphur, carbon steels can be divided into ordinary carbon steels (containing higher phosphorus and sulphur), high-quality carbon steels (containing lower phosphorus and sulphur) and high-quality steels (containing lower phosphorus and sulphur). The higher the carbon content in general carbon steels, the higher the hardness, the higher the strength, but the lower the plasticity.