To achieve a good quality kolsterised product in terms of corrosion resistance and wear resistance, it is very important to keep the contents of Delta Ferrite and Distortion Martensite to a minimum.
We recommend to specify a zero-content Delta Ferrite when purchasing your material.
The Martensite which is produced during machining can be eliminated by a solution annealing process.

Ferritic (< 0,1%C, 13-18%Cr, no Ni)eg. W.-Nr. 1.4016 (AISI 430F / X8 Cr17)

Martensitic (0,2 - 1,10%C, 12-18%Cr, 0-2,5%Ni) eg. W.-Nr. 1.4112 (AISI 440 B / X90 CrMoV18)

Austenitic (< 0,1%C, 16-26%Cr, 4-22%Ni) eg. W.-Nr. 1.4401 (AISI 316 / X2 CrNiMo 17 12)

Duplex ( <0,1%C, 21-28%Cr, 3-7%Ni, N) eg. W.-Nr. 1.4462 (SAF 2205 / X2 CrNiMoN 22 5 3)

Without Molybdenum (304)
With Molybdenum (316)
L-Grades (316L)
Stabilised (321)
Free machining (303)

In principle, any austenitic stainless steel can be kolsterised. However, the preferred type is one containing molybdenum. In addition to that Duplex stainless steel and some Nickel base alloys can be kolsterised. The table contains a selection of treatable materials and characteristics of the base material.

These are the most common materials to be kolsterised. If you have any other material, we will be pleased to check whether it is treatable.

Examples of treatable materials:

• 304, 304L
• 316, 316L (prefered standard)
• Duplex stainless steel (e.g. 2205®, 2507®)
• Hastelloy C22 and C276®
• Inconel 625 and 718®