鑄鐵與鐵鋼的閥門主要區別是含碳量不同，含碳量直接影響鋼材的強度、塑性。碳鋼也叫碳素鋼，含炭量WC小于2%的鐵碳合金。碳鋼除含碳外一般還含有少量的硅、錳、硫、磷   按用途可以把碳鋼分為碳素結構鋼、碳素工具鋼和易切削結構鋼三類。碳素結構鋼又分為建筑結構鋼和機器制造結構鋼兩種   按含碳量可以把碳鋼分為低碳鋼（WC   ≤   0.25%）,中碳鋼（WC0.25%——0.6%）和高碳鋼（WC>0。6%）   按磷、硫含量可以把碳素鋼分為普通碳素鋼（含磷、硫較高）、優質碳素鋼（含磷、硫較低）和高級優質鋼（含磷、硫更低）   一般碳鋼中含碳量較高則硬度越高，強度也越高，但塑性較低。
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.