400 Stainless Steel Companies and Suppliers

Grade 410 stainless steel is a general use stainless steel due to being able to be used in a wide selection of applications. One of the major reasons for grade 410 being so popular is its low cost compared to other high strength stainless steels, which is due to its high carbon content. The carbon content of grade 410 lowers the amount of more expensive alloys that are used in other forms of stainless and that is why grade 410 has such a low cost.

The composition of grade 410 stainless steel includes 85% iron, 11% to 13% chromium, less than 0.75% nickel, 0.08% up to 0.15% carbon, and less than 1% of manganese, silicon, sulfur, and phosphorus. The carbon content of 0.08% up to 0.15% is greater than that of other medium carbon steels, which normally have between 0.3% and 0.6% carbon content.

Much like many of the series 400 stainless steels, grade 410 is somewhat machinable, a factor that is limited due to the steel's high carbon content and having been hardened by heat treatment. It is a poor conductor of heat due to the martensitic crystalline structure and its chromium content, which is typical of all forms of stainless steel.

As with stainless steel grade 410, the crystalline structure of grade 416 is martensitic. It has the highest machinability of any stainless steel at 85%, which makes it the only free machining carbon steel. The principle of free machining means that when grade 416 is machined, it forms small chips, a factor that prevents equipment that machines grade 416 from becoming entangled. Free machining makes it possible to use grade 416 for the manufacture of precision parts and ones with complex and intricate features.

Although there are drawbacks to free machining, there are also several benefits, such as decreasing the need for workers to force grade 416 stainless steel through the machining process. Machining is faster, more efficient, produces less tool wear, and has a lower cost. An additional benefit is the high quality of the surface finishes of free machined grade 416 parts.

The level of machinability for a metal is determined by the American Iron and Steel Institute (AISI). The ability of a metal to be machined is expressed as a percentage with carbon steel at 100% being the standard. As the percentage gets lower, the machinability of a metal decreases. Grade 416 exceeds the traditional machinability of all steels with a rating of 85%, which is higher than all stainless steels that have ratings starting at 40% with the highest rating for stainless steels being 80%.

Grade 416 is resistant to the effects of acids, alkali, fresh water, and dry air but has less corrosion and rust resistance than non-machinable stainless steels. There are several techniques used to enhance the corrosion resistance of grade 416 including hardening, which gives the metal a smooth surface. To harden grade 416, it is heated between 925° C and 1010° C (1742°F up to 1850°F), after which it is oil quenched and tempered.

The excellent machining capabilities of grade 416 come at a cost in regard to its other properties. The initial cost for grade 416 is much higher than that of grade 410, which limits its use for certain applications and products. Although grade 416 has high strength and hardness, it has very poor weldability and ductility and is not recommended for applications that endure high pressure.

Unlike other forms of stainless steel, grade 416 has a sulfur content between 0.15% and 0.35%, which is one of the reasons for the metal’s high machinability. While the addition of sulfur increases the machinability of grade 416, it prevents the metal from being used for high chlorine applications and in marine environments.

The characteristics and properties of grades 410 and 416 limit their use to applications that require minimal corrosion and heat resistance but need high strength. The metals are supplied to fabricators in several forms, which include bars, sheets, plates, rolled stock, and drawn forms. The choice of forms is dependent on the product or application for which the metals will be used.

The free machining characteristic of grade 416 separates and distinguishes it from grade 410. A common use for grade 416, due to its machinability, is as components of firearms due to the strength of the metal and how it can be easily machined. In addition, due to its machinability, grade 416 is used for the production of various types of fasteners.

The low cost of grade 410 has expanded its use into a wide range of products while grade 416 can be used for the same applications but is limited in its use due to its higher cost. The characteristic that separates the two metals is the strength and toughness of grade 416.

The wide use of series 400 stainless steels is due to their high carbon content that gives the metals high strength and wear resistance. The drawback to the high carbon content is series 400 stainless steels is their limited resistance to corrosion and poor ductility. The outstanding stainless steel in the series is grade 416, which is the only free machining steel.