一、不锈钢是什么钢

1、 What is stainless steel

不锈钢是钢的一个种类，钢是指含有碳（C）量在2%以下的称之为钢，大于2%是铁。钢在冶炼过程中加入铬（Cr）、镍（Ni）、锰（Mn）、硅（Si）、钛（Ti）、钼（Mo）等合金元素改善了钢的性能使钢具有了耐腐性（即不上锈）就是我们常说的不锈钢。

Stainless steel is a type of steel, which refers to steel containing less than 2% carbon (C) and more than 2% iron. Adding alloying elements such as chromium (Cr), nickel (Ni), manganese (Mn), silicon (Si), titanium (Ti), molybdenum (Mo), etc. during the smelting process improves the properties of steel and gives it corrosion resistance (i.e. no rust), which is commonly known as stainless steel.

二、为什么不锈钢有不同的钢号

2、 Why are there different grades of stainless steel

不锈钢通常被分为201、202、301、304、309s、310s、410、420、431等多种型号。其中，201、202、301、304、309s、310s属于奥氏体不锈钢，不含有磁性，可耐多种介质腐蚀。410、420、431则属于马氏体不锈钢，具有磁性、强度高，但塑性和可焊性较差。其中硫磷含量是一很重要指标，碳素结构钢和碳素结构钢就是根据它划分的：硫，磷含量皆不超过0.04％的钢，称为钢；硫含量不超过0.03％，磷含量不超过0.035％的钢称为钢；硫磷含量各不超过0.025％的钢称为特级质量钢。

Stainless steel is usually divided into various types such as 201, 202, 301, 304, 309s, 310s, 410, 420, 431, etc. Among them, 201, 202, 301, 304, 309s, and 310s belong to austenitic stainless steel, which does not contain magnetism and can withstand corrosion from various media. 410, 420, and 431 belong to martensitic stainless steel, which has magnetism and high strength, but poor plasticity and weldability. The sulfur and phosphorus content is an important indicator, and carbon structural steel and high-quality carbon structural steel are classified based on it: steel with sulfur and phosphorus content not exceeding 0.04% is called high-quality steel; Steel with sulfur content not exceeding 0.03% and phosphorus content not exceeding 0.035% is called high-grade high-quality steel; Steel with sulfur and phosphorus content not exceeding 0.025% is called premium quality steel.

不锈钢在冶炼过程当中，由于加入合金元素品种不同，不同品种加入量的不同。其特性也是不同的，为了加以区别则冠上了不同的钢号，下面是常见装饰用不锈钢不同钢号“合金元素”含量表仅供参考：200系列：铬-镍-锰奥氏体不锈钢300系列：铬-镍奥氏体不锈钢301：延展性好，用于成型产品。也可通过机速硬化。焊接性好。抗磨性和疲劳强度优于304不锈钢。302：耐腐蚀性同304，由于含碳相对要高因而强度更好。302B：是一种含硅量较高的不锈钢，它具有较高的抗高温氧化性能。303：通过添加少量的硫、磷使其较削加工。303Se：也用于制作需要热镦的机件，因为在这类条件下，这种不锈钢具有良好的可热加工性。304：即18/8不锈钢。GB牌号为0Cr18Ni9。309：较之304有更好的耐温性。

During the smelting process of stainless steel, the amount of alloying elements added varies depending on the type of alloy element added. Their characteristics are also different, and in order to distinguish them, different steel grades are labeled. The following is a table of "alloy element" content for common decorative stainless steels of different steel grades for reference only: 200 series: chromium nickel manganese austenitic stainless steel 300 series: chromium nickel austenitic stainless steel 301: good ductility, used for forming products. It can also be hardened by machine speed. Good weldability. Wear resistance and fatigue strength are superior to 304 stainless steel. 302: Corrosion resistance is the same as 304, and its strength is better due to its relatively higher carbon content. 302B: It is a stainless steel with a high silicon content, which has high resistance to high temperature oxidation. 303: By adding a small amount of sulfur and phosphorus, it can be processed more efficiently. 303Se: It is also used to make parts that require hot forging, as this stainless steel has good hot workability under such conditions. 304: 18/8 stainless steel. The GB grade is 0Cr18Ni9. 309: Compared to 304, it has better temperature resistance.

304L：是碳含量较低的304不锈钢的变种，用于需要焊接的场合。较低的碳含量使得在靠近焊缝的热影响区中所析出的碳化物减少，而碳化物的析出可能导致不锈钢在某些环境中产生晶间腐蚀（焊接侵蚀）。304N：是一种含氮的不锈钢，加氮是为了提高钢的强度。

304L: It is a variant of 304 stainless steel with lower carbon content, used for welding applications. The lower carbon content minimizes the precipitation of carbides in the heat affected zone near the weld, which may lead to intergranular corrosion (welding erosion) of stainless steel in certain environments. 304N: It is a nitrogen-containing stainless steel, and nitrogen is added to improve the strength of the steel.

三、电梯门套常用的不锈钢有那种及区别

3、 What are the commonly used stainless steels for elevator door frames and their differences

被用于电梯门套的不锈钢主要有201不锈钢与304不锈钢以及复合不锈钢三种。

There are mainly three types of stainless steel used for elevator door frames: 201 stainless steel, 304 stainless steel, and composite stainless steel.

主要区别：1、成分：由于其成本不同，不同。304质量好一些，同时相对较贵；201相对差一些，但有一定优势；复合不锈钢介于两者之间。

Main difference: 1. Ingredients: Due to their different costs, prices vary. 304 has better quality but relatively higher price; 201 is relatively inferior, but has a certain advantage in price; Composite stainless steel is between the two.

2、组成：201组成为17Cr-4.5Ni-6Mn-N，是节Ni钢种，301钢的替代钢。经冷加工后具有磁性，用于铁路车辆。　304组成为18Cr-9Ni，是得到广泛应用的不锈钢、耐热钢。用于食品生产设备、昔通化工设备、核能等。? ?复合不锈钢为304不锈钢薄板和镀锌板加热到200℃，通过中间介质高分子膜贴合而成，产品结构紧密，具有减震、降噪、强度高等优点，由于厚度较厚，用于电梯轿厢、厅门、轿门等。

2. Composition: 201 is composed of 17Cr-4.5Ni-6Mn-N, which is a type of Ni steel and a substitute for 301 steel. After cold processing, it has magnetism and is used for railway vehicles. The composition of 304 is 18Cr-9Ni, which is the most widely used stainless steel and heat-resistant steel. Used for food production equipment, Xitong chemical equipment, nuclear energy, etc? Composite stainless steel is made by heating 304 stainless steel sheet and galvanized sheet to 200 ℃, and bonding them together through an intermediate medium polymer film. The product has a tight structure and advantages such as shock absorption, noise reduction, and high strength. Due to its thick thickness, it is used for elevator cars, hall doors, car doors, etc.

3、201是含锰较高,表面很亮带有暗黑的亮,含锰较高容易生锈。304含铬较多,表面呈现哑光,不生锈.两种放在一起就有比较了。重要的就是耐腐蚀性能不同,201的耐腐蚀性能很差,所以就要便宜很多.又因为201含镍低，所以比304的低，于是耐腐蚀性能就不如304的了。复合不锈钢表面由304组成，表面具有304不锈钢的特性。

3. 201 has a high manganese content, with a bright and dark surface, and is prone to rusting due to its high manganese content. 304 contains a lot of chromium, with a matte surface and no rusting. The two types can be compared together. The most important thing is that the corrosion resistance is different. 201 has poor corrosion resistance, so the price is much cheaper. Also, because 201 contains low nickel, the price is lower than 304, so the corrosion resistance is not as good as 304. The surface of composite stainless steel is composed of 304 and has the characteristics of 304 stainless steel.

4、201不锈钢在特定环境下会生锈，譬如说放置于盐水浸泡就会生锈，但是日常环境下是极不易生锈的。不锈钢材质是因为含有镍元素，才有不易生锈的能力，而相较于304不锈钢来说，201不锈钢中的镍元素会更少，因此要比304不锈钢更容易生锈。复合不锈钢的表面材质为304不锈钢，而生锈主要表层氧化，因此复合不锈钢抗锈蚀能力优于201不锈钢。

4. 201 stainless steel will rust in specific environments, such as soaking in salt water, but it is extremely difficult to rust in daily environments. Stainless steel material has the ability to resist rusting due to its nickel content, and compared to 304 stainless steel, 201 stainless steel contains less nickel, making it more prone to rusting. The surface material of composite stainless steel is 304 stainless steel, and rust is mainly caused by surface oxidation, so the corrosion resistance of composite stainless steel is better than that of 201 stainless steel.

不锈钢具有抵抗大气氧化的能力——即不锈性，同时也具有在含酸、碱、盐的介质中乃腐蚀的能力——即耐蚀性。但其抗腐蚀能力的大小是 随其钢质本身化学组成、加护状态、使用条件及环境介质类型而改变的。如304钢管，在干燥清洁的大气中，有优良的抗锈蚀能力，但将它移到海滨地区，在含有大量盐份的海雾中，很快就会生锈了；而316钢管则表现良好。因此，不是任何一种不锈钢，在任何环境下都能耐腐蚀、不生锈的。

Stainless steel has the ability to resist atmospheric oxidation, that is, stainless steel, and also has the ability to corrode in media containing acid, alkali, and salt, that is, corrosion resistance. But the magnitude of its corrosion resistance varies with the chemical composition of the steel itself, the state of protection, the conditions of use, and the type of environmental medium. Like 304 steel pipe, it has absolutely excellent corrosion resistance in dry and clean atmosphere, but when moved to coastal areas, it will quickly rust in sea fog containing a large amount of salt; And 316 steel pipes perform well. Therefore, not any type of stainless steel can resist corrosion and rust in any environment.

当不锈钢管表面出现褐色锈斑（点）的时候，人们大感惊奇：认为 “不锈钢是不生锈的，生锈就不是不锈钢了，可能是钢质出现了问题”。其实，这是对不锈钢缺乏了解的一种片面的错误看法。不锈钢在一定的条件下也会生锈的。

When brown rust spots (dots) appear on the surface of stainless steel pipes, people are greatly surprised: they believe that "stainless steel does not rust, and if it rusts, it is not stainless steel anymore. It may be a problem with the steel. In fact, this is a one-sided misconception about the lack of understanding of stainless steel. Stainless steel can also rust under certain conditions.

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