Corrosion resistant stainless steel

Stainless steel - chemical composition and characteristics

For the determination of corrosion-resistant steel, the iron alloy must be considered, in which the basic element giving its properties is Chromium - Cr with a minimum content of about 12-13% of the product weight in general terms. Nickel-Ni is most commonly used in conjunction with Chromium, thanks to which was made the most common corrosion-resistant steel 18/8 (0H18N9 - X5CrNi18-10 - AISI 304), which is treated with various alloying additives as well as limiting the ranges of certain elements to form new grades of steel.

Failing to complete this thesis with information on maintaining a relatively low carbon level in the composition, it could be considered that the tool steel could also be stainless (eg NC11LV). Carbon-C, which is always present, is making steel more prone to corrosion. In order to prevent this, in proportion to the increasing range of carbon, an amount of chromium should raise in the composition. Otherwise, the material will be covered with rust in demanding environments.

It is likely that carbon might not be a welcome element in corrosion resistant steels. It influences decisively the structure of steel, at its low concentration the steel is soft, has no suitable mechanical properties, and is not used for hardening. In addition, it is worth mentioning that Chromium with Carbon are creating chromium carbides on the surface of the product.

Apart from Chromium, the second primary element supplemented by stainless steel is Nickel - Ni. Other occurring elements are: Manganese - Mn, Silicon - Si, Aluminum - Al, Molybdenum - Mo, Copper - Cu, Cobalt - Co, Tungsten - W, Niobium - Nb, Selenium - Se, and Titanium - Ti.

They are alternately referred to as corrosion-resistant steel, acid-resistant steels, stainless steels, INOX steels (fr. inoxydable - stainless).

Stainless and acid-resistant bars, pipes, sheets, strips, forgings

The above-described stainless steels, acid-resistant steels, or generally referred to as corrosion-resistant steels define PN-71/H-86020, PN-83/H-84017, IS-63/0642-01, IS-63/0644-02, and current euronorm PN-EN 10088-1, PN-EN 10155 according to which are delivered:

• Acid-resistant and stainless seamless and seamed tubes according to PN-85/H-74242, PN-96/H-74245, PN-EN 10216-5, PN-EN 10217-7, PN-EN 10296-2, PN-EN 10297-2, PN-EN 10312, PN-EN ISO 13680, PN-EN 10263-5,
• Stainless and acid-resistant sheets according to PN-83/H-92128, PN-86/H-92138, PN-EN 10088-2, PN-EN 10028-7, PN-EN 10088-4
• Acid-resistant and stainless forgings and forged bars according to PN-91/H-94053, PN-EN 10250-4, PN-EN 10222-5
• Acid-resistant and stainless cold-rolled stripes wg PN-93/H-92332, PN-EN 10088-2, PN-EN 10259, PN-EN 10028-7, PN-EN 10151, PN-EN 10088-4
• Acid-resistant and stainless bars according to PN-93/H-93004, PN-EN 10088-3, PN-EN 10272, EN 10058, EN 10059, PN-EN 10269, DIN 1013, DIN 7527, DIN 1017, PN-EN 10294-2, EN 10028-7
• Sections and profiles made of stainless and acid-resistant steel according to PN-EN 10056, PN-EN 10279, PN-EN 10055, DIN 59370, DIN 1029, DIN 1028, DIN 1022, PN-EN 10088-3
• Acid-resistant and stainless light bars according to PN-93/H-93004, PN-EN 10278, DIN 1018, DIN 671, PN-EN 10088-5, PN-EN 10088-3, EN 10263-5
• Acid-resistant and stainless wires according to PN-EN 10264-4, EN 10263-5 PN-EN 10088-3, PN-EN 10088-5