不锈钢“304”及其衍生牌号的标准化学成分

不锈钢牌号“304”（S30400）是美国不锈钢标准（如ASTM标准）中的牌号名称,它是18—8型Cr—Ni奥式体不锈钢的典型牌号,由于其具有优良的综合性能,用途十分广泛,其产销量占到奥式体不锈钢的80％左右。对304及其衍生牌号,美国材料和试验协会不锈钢牌号标准ASTMh959-04和日本JIS、我国GB、国际ISO、欧洲EN等不锈钢标准中都有明确的规定。但是,近期我国国内市场上出现了没有列入国内外标准的304衍生牌号（如304J5,含镍量只有4．3％）,或者与日本JIS中的304J1、304J2名称相同但成分有出入的产品。对此,我们专门约请冶金材料标准专家伍千思写了这篇“不锈钢‘304’及其衍生牌号的标准化学成分”文章,详细介绍了国内外关于304及其衍生牌号的标准化学成分。我们希望,企业如果生产日本JIS板材标准中的304J1、304J2,成分、性能必须符合其标准要求;生产者和经销商必须向用户指明这些产品的特定用途（如适用于作一般耐蚀条件下用的通过冷加工成型的部件或制品）,我们不主张生产和销售没有列入国内外标准的304衍生牌号产品,以避免给消费者带来误解和损失。     

努力节省奥氏体不锈钢中的镍

304型不锈钢具有优良的使用成本特性、成型性和耐腐蚀性。因此,这类钢得到广泛地应用,包括家庭用品、建筑材料、汽车零件和化工与食品工业用材料。然而,这些用途并不需要304型不锈钢的所有性能。换句话说,只要其他类型的不锈钢可满足某种用途必需的性能就可代替304型不锈钢使用。     

耐海水腐蚀性优良的不锈钢复合钢板

最近,日本钢管公司研制成功耐海水腐蚀不锈钢复合钢板,这在世界上尚属首创。 随着海洋开发事业的发展,化工设备的海水热交换器和海水淡化装置等需要耐海水腐蚀性优良的材料。众所周知,从耐海水腐蚀性这一点看,SUS304、316耐蚀型不锈钢,在附着生物的“耐裂隙腐蚀性”、“耐点腐蚀性”方面尚很不佳。因此,目前很少利用这些材料。已开发并采用的耐海水腐蚀性能优良的不锈钢有高Ni-Cr系钢种,但价格相当昂贵。因此,人们期望开发耐海水腐蚀性能优良、价格便宜的不     

经济型双相不锈钢的研发进展

 经济型双相不锈钢是一种高性能低成本的氮合金化不锈钢新材料,具有典型的铁素体-奥氏体双相组织。利用氮取代镍元素的奥氏体化作用,降低成本的同时获得优良的力学性能和耐腐蚀性能。介绍了经济型双相不锈钢的发展历史,重点讨论了合金元素和热处理对相变、力学性能和耐腐蚀性能的影响规律,并与304和316进行对比;同时,分析了经济型双相不锈钢焊接性能和焊接工艺的研究进展。经济型双相不锈钢S32101、S32003、S32202等,已用于核电、桥梁、建筑、热交换器等行业,取代传统奥氏体不锈钢AISI 304和316。由于经济型双相不锈钢具有高强度和优良耐蚀性,同时镍、钼等贵金属的含量都较低,已成为未来不锈钢发展的方向之一。     

B443超低碳氮铁素体不锈钢的研究

为开发价格昂贵的SUS304奥氏体不锈钢的替代产品,试验研究了不同含量C N和Nb,Ti稳定化对B443系列铁素体不锈钢再结晶组织、力学性能、点蚀电位的影响.试验结果表明,Nb,Ti双稳定化提高了B443铁素体不锈钢的再结晶温度和点蚀电位.在试验室研究基础上,宝钢不锈钢分公司试制了B443NT超低碳氮铁素体不锈钢.该产品不仅具有与SUS304相当的耐腐蚀性能,而且具有优良的深拉伸性能和满意的焊接性能,可用于运输、建筑、厨具等众多行业.     

443高铬铁素体不锈钢耐蚀性能评价

通过盐雾试验、电化学试验和应力腐蚀试验,并结合扫描电镜,对比研究了443超纯铁素体不锈钢和304奥氏体不锈钢的耐腐蚀性能。结果表明:碳、氮间隙元素极低的高铬443超纯铁素体不锈钢点腐蚀速率小于304奥氏体不锈钢,具有比304更优异的耐氯离子腐蚀性能;同时,443不锈钢不具有晶间腐蚀敏感性,而304具有严重的晶间腐蚀敏感性;304不锈钢有可能发生应力腐蚀断裂,443不锈钢没有这种危险。可见,443超纯铁素体不锈钢是304奥氏体不锈钢理想的替代材料,可用于电梯、建筑装饰、厨具等众多行业。     

不锈钢在醋酸中的耐蚀性行为研究

本文采用全浸蚀试验失重法，对五种牌号不锈钢在不同浓度、温度的醋酸介质中的一般腐蚀耐蚀性进行了比较；研究了304、321不锈钢在醋酸中的耐晶间腐蚀性及醋酸中微量杂质对不锈钢耐蚀性的影响。     

不锈钢概论（10）

3．2．2马氏体铬镍不锈钢性能特点 传统马氏体铬镍不锈钢中,最早的代表性牌号是1Cr 17Ni2,而低碳和超低碳的高韧性、可焊接铬镍马氏体不锈钢则是马氏体铬镍不锈钢的新进展,它们合金化的目的和合金化的方向见表3．4。     

我国含钼不锈钢的应用前景十分看好

据《安泰科》报道 ,从“钼应用技术推广国际合作研讨会”获悉 ,进入 2 1世纪 ,随着我国国民经济的增长及人民生活水平的提高 ,工业生产的迅猛发展以及环境保护的需要 ,都将扩大不锈钢的应用 ,同时也对不锈钢提出了更高的质量要求。例如 ,对海洋的开发、核能的利用、石油化工工业的发展和水的储存、输送、环保设施的制造 ,都需要大量质优的耐蚀材料。因此 ,2 1世纪末 ,国内外都在着手进行不锈钢的开发 ,并对现今的四大不锈钢类试制成功了“超级”牌号。其共同特点是 ,从成分上保证更稳定的组织、更优良的耐蚀性能及更好的力学性能。钼金属是…     

新开发电磁不锈钢

日本山阳特殊制钢开发了冷锻性非常优异的电磁不锈钢“QMR2L”，它成为电磁不锈钢的第5个牌号，作为QMR系列化，相应形成用户需要的体制，其目的是想扩大既有高耐蚀性能又具有优异电磁性能的钢种方针。     

Duplex Stainless Steels ‐ a Review after DSS ‘07 held in Grado

Duplex stainless have always been an exiting area of interest for researchers, stainless steel producers, fabricators and end users. They present very diversified technical challenges and simultaneously attractive in‐service properties at excellent cost/properties ratios, particularly in critical markets including oil and gas, chemical industry, pulp and paper industry, water systems, desalination plants, pollution control equipments, chemical tankers, etc. This explains why although they still remain a marginal production in the stainless steel business (less than 1%) dedicated international conferences have been organised since about 25 years. The purpose of this paper is to present a review of the 100 scientific contributions presented during the latest international duplex stainless steel conference witch took place in Grado, Italy, on 18‐20 June 2007. The main topics concerned microstructure and mechanical properties, weldability, corrosion resistance and in‐service properties. The “standard” duplex stainless steels, i.e. the 2304, 2205, and the family of 2507 (Cu,W, ...) grades were confirmed as very valuable grades with outstanding performances proven in more than 20 years successful in‐service applications. New grades including the so‐called lean duplex dedicated to volume oriented markets (possible replacement of 304/316 grades) and some “niche” grades dedicated to very specific markets were presented. It was pointed out that the duplex grades start to be well established products particularly suitable for corrosion resistance applications. They show a two‐digit yearly growth thanks to the production of new grades and production ranges (coils and bars) targeting the replacement of the more costly 300 series including 304 but also rusty carbon steel in e.g. structural application.     

High corrosion resistance 21%Cr-0.4%Cu ferritic stainless steel contributing to resource conservation

With prices for metal resources such as nickel and molybdenum soaring,there is a heightened sense of crisis concerning resource scarcity.While Type304,the most common stainless steel,offers excellent corrosion resistance,its price is affected significantly by the cost of nickel because of its 8%nickel content.The stainless steel that has the same corrosion resistance as that of Type304 and does not contain nickel and molybdenum has been required.JFE Steel Corporation has developed a new 21%Cr-0.4%Cu stainless steel,the world’s first ferritic stainless steel,which offers equivalent corrosion resistance to Type304 while containing absolutely no nickel or molybdenum,two rare metals.The newly developed steel contains 21%chromium with the addition of 0.4% copper.The development of the steel is based on a new discovery that the passive films of stainless steels could be strengthened by the synergy effect of high chromium content and copper addition.Copper addition enriches the chromium content in passive films after field exposure.Newly developed 21%Cr-0.4%Cu stainless steel is adopted for many applications as a substitution for Type304,including commercial kitchenware,building materials and industrial machinery.The steel is expected to be a new standard of a ferritic stainless steel as a substitution for Type304.     

The“state of the art”slab caster for stainless steel in ThyssenKrupp Acciai Speciali Terni

On April 23,2009,a new single strand slab caster at ThyssenKrupp Acciai Speciali Terni(TKAST) was successfully started up with the first cast of AISI 304 grade in Terni plant,central Italy.TKAST is the Italian company of ThyssenKrupp Stainless group. The new caster is designed for a total capacity of approx.900.000 tpy of stainless steel slabs covering the complete range of stainless grades,including AISI 300 and 400 families(austenitic,ferritic and martensitic grades).This state of the art caster for the production of 215 mm thick slabs replaced an existing thin slab caster. This paper resumes the reasons of the installation of the new plant designed,manufactured erected and commissioned by Danieli and describes the technological solution,main features as well as the excellent results of this state of the art caster.     

Crystallization Extent and Phase Constitution of Slag Films Taken from Continuous Casting Moulds for Stainless Steels

Slag film samples were taken from the mould wall after casting of stainless steel slabs of grade 304, 321, 409L and 430, which represent austenitic, ferritic and titanium stabilized stainless steels. The chemical compositions of the samples were analysed and their phases were identified using a combination of scanning electron microscope (SEM), energy dispersive X‐ray analysis (EDX) and X‐ray diffraction (XRD). Finally the crystallization ratio was determined by SEM. The results show that the chemical compositions of the films during casting differ from the original designed flux composition. Concerning the heat transfer in the mould, the film taken during casting of steel grade 304 showed the highest insulation ability whereas the film taken during casting of steel grade 409L had the lowest insulation ability. The films taken during casting of steel grades 321 and 430 showed average heat insulation abilities. The solidification conditions in the mould during casting of steel grades 304, 321, and 409L matched the solidification requirements of the corresponding steel grades. However, the basicity of the powder for steel grade 430 should be decreased a little in order to improve the lubrication function and counteract sticking tendencies. Perovskite crystals, which usually precipitate at relatively high temperature, were found in the film taken during casting of steel grade 321. This is harmful in view of the safety of the casting process and the surface quality of the slab.     

Q235/304碳钢-不锈钢复合板界面结合的有限元模拟

应用MARC软件对304不锈钢(%:17～19Cr、8～11Ni)/Q235碳钢(%:0.14～0.22C)复合板前5道次往复热轧过程(变形率%:3.4、10.4、25.0、37.8、49.4)进行有限元模拟,得出Q235钢和304不锈钢在界面处的应力和应变分布。模拟结果表明,在两种材料都进入塑性变形状态时,界面处法向应力值达到或超过304不锈钢界面温度下的变形抗力,且两种材料应变平均值的差值≤0.01时即可复合,该模拟结果与生产试验结果一致;这说明使用小的单道次变形率,大的累积变形率可获得结合良好的碳钢/不锈钢复合板。     

宝新深冲产品应用分析

为开发深冲用冷轧不锈钢产品（即DDQ产品）,扩大宝钢不锈钢在冷冲压制品市场的占有率,在对奥氏体不锈钢形变理论分析及冷冲压制品市场调研的基础上,对304系列钢种中的304Ni8.5、304Ni9及SUS304Cu按不同工艺进行了试制生产,并将试制产品供不同成形方式制品加工试用。试用结果表明：宝新304Ni8.5、304Ni9及SUS304Cu深冲系列产品具有较好的流动性,较适合于热水器内胆等以拉深成形为主要成形方式的冲压加工,其中304Ni8.5及SUS304Cu的极限深冲比在2.4以上、304Ni9的极限深冲比可达2.9以上,而水槽等以胀形为主要成形方式的冲压制品,使用宝新一般冲压类产品更为适合。     

三步法和二步法不锈钢冶炼工艺的分析和生产实践

分析了HM DEP-KOBMS-VOD三步法(铁水脱硅和脱磷预处理-KOBMS转炉脱碳、合金化-真空吹氧脱碳)和EAF/BOF-AOD二步法(电弧炉炼300系不锈钢母液/400系钢转炉脱磷-氩氧脱碳和合金化)生产不锈钢的生产效率和成本。三步法工艺生产铬不锈钢和超低碳氮不锈钢具有生产效率高、氩气消耗低、P-Cu-Pb有害杂质含量低的优势,而EAF-AOD二步法工艺生产304、316L等铬镍不锈钢有可使用含镍生铁、不锈钢废钢、生产成本低,效率高的优势。文中介绍了太钢用三步法和二步法工艺生产的不锈钢品种结构和工艺实践。     

304不锈钢与200系列不锈钢识别剂的研制及其应用

200系不锈钢与304不锈钢外观比较相似,肉眼无法识别,由于其价格较低常冒充304不锈钢混入食品接触性用具领域,给食品安全带来不确定性危害。为防止200系不锈钢冒充304不锈钢使用,实验研制了304不锈钢配方试剂(识别剂)用以快速区分200系列与304不锈钢。配方试剂在非通电型分析液基础上进行改进,即分别将固体五水硫酸铜、氨基磺酸、氯化钠研磨至74μm以下,然后将3种试剂按照物质的量之比为1∶4∶12混合后加水快速溶解,滴于不锈钢表面打磨处,在5s内变红的样品为200系列不锈钢,在1min内不变色的样品为304不锈钢。将该识别剂用于200系列及304不锈钢定值样品(用GB/T 11170—2008法定值)及超市随机抽取50个不锈钢样品的鉴别,现场鉴别结果同实验室结果吻合。该配方试剂由3种固体物质混合而成,其更环保、安全、便捷,便于200系列和304不锈钢的现场鉴别。     

Inclusion control of ultra clean ferritic stainless steel

The most important characteristics of the ultra clean ferritic stainless steel is that the carbon,nitrogen and other interstitial elements are very low.The ultra clean ferritic stainless steel has been widely used for household appliances,auto exhaust system,elevator,water treatment system,building roof and other various fields,because of its low cost,pro-environment,excellent properties.They can replace some traditional austenitic stainless steel.such 304 and 316L.The addition of titanium to liquid steel has become common for stabilizing nitrogen and carbon in steel.Titanium reacts with nitrogen,carbon,and oxygen to form titanium nitride,carbide, carbonitride and oxide.These inclusions may have a deleterious effect on the properties such as toughness, ductility,weldability and corrosion.In addition,the inclusions can also agglomerate and cause surface quality problem of the slab and clogging of the submerged entry nozzle during continuous casting process. The formation rules of inclusions in ultra clean ferritic stainless steel were investigated by the thermodynamic calculation,and methods of controlling inclusions were put forward to improve the quality of product.The composition,type,amount,size and distribution of the inclusions in the slab are investigated by optical microscope and scanning electron microscope.The results can be concluded as follows.（1） In the slab,the main original inclusions,with size of larger than 2μm,are Al₂O₃,TiN or Ti（CN） and complex TiN or Ti（CN） inclusion with core of MgO,MgO-Al₂O₃ and Ti₂o₃,which will not affect the performance of the steel if they are in diffusing distribution.The size of these inclusions are less than 10μm except some Al₂O₃ inclusions in size of 10-40μm.（2） Foreign inclusions are Ti₂O₃-Al₂O₃-MgO-SiO₂ in size above 50μm covered by TiN or Ti （CN）.Although these inclusions are few,they do harm to the surface quality of stainless steel.It is able to reduce the risk of forming this kind of inclusion by aluminium deoxidation with increasing Al content to restrain the formation of Ti₂O₃.（3 ） TiN or Ti（CN） is easy to precipitate on inclusions such as MgO,MgO-Al₂O₃ and Ti₂O₃,except Al₂O₃.Controlling the content of[Ti]and[N]and the formation of the oxides can be used to control the precipitation of TiN or Ti（CN）.