When we talk about stainless steels is important to know the differences between the two most commonly used types 304 and 201, each one has its own chemical composition as well as advantages and disadvantages, beside specific characteristics as hardness, corrosion resistance, welding, and appearance among others, each of these features is what makes each type ideal for some projects. In the chart below is a direct comparison between 304 and 316 surgical stainless steel. Both type 304 and type 316 stainless steel belong to the 300 series of stainless steel alloys austenitic alloys that are specifically formulated for forming and drawing stainless steel sinks. When it comes to variations between 304 and 304l stainless steel, the most essential thing to note is the latters greater immunity to intergranular corrosion. While grade 304 stainless steel only has trace amounts of it, aisi 316 has considerably more. Why is ss 316 better than ss 304 for sea water but the. Just a quick question for all you stainless steel experts out there.
Stainless steels austenitic stainless steels include the 200 and 300 series of which type 304 is the most common. Due to the addition of molybdenum, grade 316 stainless steel is more corrosion resistant than similar alloys, such as 304 stainless steel. Chemical and physical properties are in accordance with en 10088. It is the oxide layer on the surface which actually prevents the ss from rusting, and the oxide layer can be injured. Difference between 304 grade and 316 grade stainless steel. A closer look into type 316 as compared to type 302304 and common uses. Intergranular corrosion is the cracking that can occur along grain boundaries of steel in the presence of tensile stress. Stainless 316, 316l, 317, 317l united performance metals.
Care was taken to include as much information as possible about stainless steel flat products used throughout europe, for the informatio. Some waterless cookware companies in an effort to try and distinguish themselves from their competition promote the fact that they use 316 surgical stainless steel rather than 304 surgical stainless steel. Often used for pumps, valves, chemical equipment and marine applications. Aug 19, 2015 304 stainless steel vs 316 stainless steel that makes stainless steel what it is, making up a minimum of 10. Stainless steel type 304 or type 301 why does it matter. Cost difference between ss 304 and 316 l cr4 discussion thread. The steel contains both chromium between 18% and 20% and nickel between 8% and 10. The main difference between type 304304l and type 316316l is the addition of 23 wt% molybdenum in the latter.
Of the wide range of stainless steels on the market, both type 304 and type 316 stainless read more. The material used in the present study is 304 stainless steel, the chemical composition of it is shown in table i. The moly is added to improve the corrosion resistance to chlorides like sea water. Sep 25, 20 given that type 316 stainless steel alloy contains molybdenum it has a considerable more resistance to chemical attack than 304. In the annealed condition it is essentially nonmagnetic and becomes slightly magnetic with the application of cold work. Grade 304 ss stands up to a variety of environments, while grade 316 ss has improved resistance to chlorides and other corrosives.
Why is ss 316 better than ss 304 for sea water but the other. This is why marlin steel typically stocks grade 304 and grade 316 stainless steel. The difference between 304, 304l and 304h stainless steel. Type 304 vs type 316 stainless steel sinks and faucets. British stainless steel associationmaking the most of stainless steel as american aisi basic grades, the only practical difference between 304 or 316 there are two european steels of.
Nominal composition of ss304 and ss316 coupons used in this study. In addition to this, the nickel content in type 316 stainless steel is higher than that in type 304 stainless steel. The common austenitic grades of stainless steel, 304 and 316, are also. Test for difference between type 316 and 304 stainless steel. Understanding magnetic properties of 304 and 316 stainless. In the above example, the surface of the rivets will be small compared to that of the stainlesssteel sheet. Type 316 stainless steel is an austenitic chromiumnickel stainless and heatresisting steel with superior corrosion resistance as measured up to other chromiumnickel steels when exposed to many types of chemical corrodents. At first glance, the chemical compositions of aisi 304 and aisi 316 dont differ much. The primary alloying additions are chromium and nickel. Its important to understand when selecting a grade of stainless steel ss for your application or prototype, if the material needs to have magnetic properties or not. When dealing with stainless steel materials, people often have a tough time differentiating between 304 grade stainless steel and 316 grade stainless steel.
Again, 316ss is more resilient as it is less susceptible to corrosion from chlorine solutions than 304ss, which shows signs of corrosion at 2 ppm of chlorine and 316ss showing signs. It accounts for more than 50% of all stainless steel produced, represents between 50 and 60% of australias consumption of stainless materials and finds applications in almost every industry. Selection of an ideal grade of stainless steel must meet the corrosion resistance needs along with the physical or mechanical properties. Type 304 stainless steel is the most widely used of the austenitic chromiumnickel stainless steels.
Chemical composition 304 chemical composition 316 carbon 0. Stainless 316 contains more nickel than stainless 304, while 304 contains more. F amilies of stainless steel 9 10 medium and high crbased jfemh1 15cr1. Type 316 stainless steel in an environment of 25% phosphoric acid, and figure 3 shows effects of temperature on types 304 and 316 in very concentrated sulfuric acid. Feb 18, 2004 grade 316 is the standard molybdenumbearing grade, second in importance to 304 amongst the austenitic stainless steels. Ferritic stainless steels are nonhardenable fecr alloys.
Magazine stainless steel stock guide assda food code of practice blue book. Stress corrosion cracking of various stainless steels is critical in matching type to application. Whats the difference between 304l and 316l stainless. Westlock controls use fasteners made from various stainless steel materials with 304 being the most common and 316 being used to complement the cf8m stainless steel versions of our products. The molybdenum gives 316 better overall corrosion resistant properties than grade 304, particularly higher resistance to pitting and crevice corrosion in chloride environments. Its main function in stainless 316 is to help fight off corrosion from chlorides.
Stainless 316 contains more nickel than stainless 304, while 304 contains more chromium than 316. A discussion started in 2000 but continuing through 2018. Stainless 304 usually consists of 18% chromium and 8% nickel. Differences between ss304 and ss316 stainless steel. As 316 contains molybdenum, it has a higher resistance to chemical attack than type 304. Type 304 vs type 316 stainless steel sinks and faucets by just. Lowcarbon versions, such as 316l or 304l, have carbon contents below 0. Use 309l including er309lsi when joining mild steel or low alloy steel to stainless steels, for joining dissimilar stainless steels such as 409 to itself or to 304l stainless, as well as. The higher molybdenum content results in grade 316 possessing increased corrosion resistance.
So, while 316 stainless steel is generally considered more corrosion resistant than 304, depending on the nature of the corrosive media the corrosion rates of. We make a special type of tapping screw from 410 stainless because of its hardening capabilities and our requirement to produce a hardened drill tip. Since type 316 stainless steel alloy contains molybdenum bearing it has a greater resistance to chemical attack than 304. It is considerably more resistant to solutions of sulfuric acid, chlorides, bromides, iodides and fatty acids at high temperature. The place to start uns s30400 grade 304 is the greatest stainless success story. Type 304 stainless steel is used in enclosures, storage tanks, pressure vessels and tubing or piping. Care was taken to include as much information as possible about stainless steel flat products used throughout europe, for the informatio n of the user. The molybdenum allows ss 316 to be more resistance to corrosion overall, with specific resistance against chlorine pitting. Other applications include fasteners and screens for the mining industry. Before determining this, it is good to understand what makes a grade of stainless steel magnetic or not. Each of these alloys are highperforming in terms of tensile strength, durability, and corrosion resistance. The two most common stainless steel grades are 304 and 316.
Sae 304 stainless steel is the most common stainless steel. When we talk about stainless steels is important to know the differences between the two most commonly used types 304 and 201, each one has its own chemical composition as well as advantages and disadvantages, beside specific characteristics as hardness, corrosion resistance, welding, and appearance among others, each of these features is what makes each type ideal. Service tests are most reliable in determining optimum material, and astm g4 is a recommended practice for carrying out such tests. Ss316 is better than ss304 in terms of corrosion resistance, heat resistance and certain properties, but the price is higher than aisi 304, for more details, please check stainless steel grade 304 vs 316, and 316 vs 316l. The main difference between type 304 304l and type 316 316l is the addition of 23 wt% molybdenum in the latter. A few percentages this way or that in chromium and nickel.
Type 316 is durable, easytofabricate, clean, weld and finish. Why 316 stainless steel is better than 304 stainless. Cost difference between ss 304 and 316 l cr4 discussion. Types 316 uns s31600, 316ls31603, 317 s31700, and 317l s31703 are molybdenum bearing austenitic stainless steels which are more resistant to general corrosion and pittingcrevice corrosion than the conventional chromiumnickel austenitic stainless steels such as type 304. Asme standards are generally based on the appropriate astm standards, but the standard numbers are preceded with the letters sa, rather than just the a of the astm standards. Pdf corrosion study of ss304 and ss316 alloys in atmospheric.
Why 316 stainless steel is better than 304 stainless steel mill. Typical material specification and difference ss 304, 316. A major difference between 304 and 316 stainless steel is the chemical composition, with 316 containing a significant amount of molybdenum. Most astm and asme standards list the steel grades by their uns unified numbering system numbers but also make reference, where appropriate to the more general aisi american iron and steel institute grade designations. Stainless steel 316 is a chromiumnickel based steel that possesses increased levels of resistance against several substances, due to the addition of molybdenum in its composition. Grade 316 has virtually the same mechanical, physical and fabrication characteristics as 304 with better composition. Outwardly, 304 stainless steel and 316 stainless steel look very similar. The simple answer is 304 contains 18% chromium and 8% nickel while 316 contains 16% chromium, 10% nickel and 2% molybdenum. British stainless steel associationmaking the most of stainless steel as american aisi basic grades, the only practical difference between 304 or 316 there are two european steels of the 304l type, 1. Types 405, 409, 430, 422 and 446 are representative of this group. Socalled 304 with 316 stainless steel bar, it is according to the astm standard to produce a brand. Type 304 stainless steel an overview sciencedirect topics. Chemical compositions of aisi astmasme and uns austenitic stainless steel grades introduction aisi astm asme and uns. Again, 316ss is more resilient as it is less susceptible to corrosion from chlorine solutions than 304ss, which shows signs of corrosion at 2 ppm of chlorine and 316ss showing signs of corrosion at 4 ppm of chlorine.
Molybdenum is a chemical element used for the strengthening and hardening of steel. The most basic difference between the grades of steel is the presence of molybdenum in stainless 316. The other element that is of importance is the carbon content of the stainless steel. What is the difference between stainless steel 310 and. The key difference is the addition of molybdenum, an alloy which drastically enhances corrosion resistance, especially for more saline or chlorideexposed environments. Chemical composition % of austenitic stainless steel grades used for spirol coiled spring pins. The lack of understanding that persists can be justified given the fact that on the surface, the two grades of stainless steel in question look extremely similar, if not identical. Sep 27, 2012 since type 316 stainless steel alloy contains molybdenum bearing it has a greater resistance to chemical attack than 304.
Is 316 stainless steel worth the extra cost over 304. Stainless steel grades explained 304 vs 316 danver. From a chemical point of view, 304 stainless steel contains 18% chromium and 8% nickel while 316 stainless steel contains 16% chromium, 10% nickel and 2% molybdenum. Understanding magnetic properties of 304 and 316 stainless steel. Stainless steels aisi 304 vs aisi 316 the difference. Nickel gives stainless steel hardness and strength.
It is less electrically and thermally conductive than carbon steel and is essentially nonmagnetic. Magnetism although stainless steel 304, 316 and cf8m grades are normally viewed as nonmagnetic, they. Stainless steel distributor 301 stainless steel 304 and 304l stainless steel 316 and 316l stainless steel other 300 stainless series 409 stainless steel 439 stainless steel 430 stainless steel other 400 stainless series aluminum. The corrosion rate of stainless steel is also compared with those reported for other international. Whats the difference between 304 and 316 stainless steel. One of these ss alloys is more susceptible under flexing stresses to such intrusive chloride d. In different countries and regions, has a different name. Cf8m and cf3m are the cast equivalents of 316 and 316l, respectively. Stainless steel specification and composition chart. Composition limits for 304 and 304l are identical except for carbon content 304l does permit up to 12.
Chemical differences between 304l and 316l stainless steel. American society of mechanical engineers asme publish design codes and standards for pressure applications. This reduces pitting from chemical environments and allows grade 316 stainless steel to be used in highly acidic and caustic environments that would otherwise eat away at the metal. Chlorine also has an effect on the degradation of 304 ss and 316 ss. Influence of high temperature on corrosion behavior of 304. Type 304l stainless steel is preferred in welding applications to exclude the formation of chromium carbides during cooling in the heat affected. Kad group of companies provide stainless steel chemical composition table chart. Bsc, msc, phd, mim, ceng, in plant engineers reference book second edition, 2002. They also have excellent toughness and can be used in the food, marine, chemical and architectural fields. Stainless 316 is made up of 16% chromium, 10% nickel and 2% molybdenum. It depends on the shapes involved and the local spot market, among other possible things. I must apologize right off if my answer is incorrect.
Sep, 2016 i must apologize right off if my answer is incorrect. There is a possibility that another steel would be a better choice, check with your steel supplier. In addition, these fasteners will be used in external environments where corrosion is an obvious concern. The chemical composition of these two types of stainless steels is given in table 5.
1313 423 590 1111 1513 594 1382 36 1162 154 361 85 1285 1082 691 382 284 673 843 257 572 686 498 1451 228 353 1530 522 1325 881 1241 301 476 719 1096