c-g-designs

METALS (2)

            THE ‘STAINLESS STEELS.

            This category is not totally corrosion-free, but its hi-chromium-Nickel content  makes it highly corrosion-resistant .

            There is a distinction between the Austenitics (class 300)  and the Martensitics (serie400). As the 4 digits AISI/ASTM american norm is the most widely used, the european norm will only be used for the compositions. The carbon contents are here also 1/100 of the indications, while the additions are the full numbers.     

            Only the grades prone to be used  in our application will be mentioned.

            -304 ( X5CrNi 18-10). Used for parts with low constraints.

            -316 (X5CrNiMo 18-10). Better mechanical characteristics than the 304. Accept a hight bright polish.

            -416 (X12CrS13). Improved machine-ability by addition of sulphur. Low Rm at 60kgs/mm². Despite its low characteristics, it is universally used  for barrel making for its ease of machining,despite its limited  mechanical properties.

            -420 (X20Cr13). Good machanical characteristics alloy (Rm=80kgs/.mm²). It is most certainly better suited than the 416+S fpr barrel making.

            -440c (X105CrMo17).  High characteristics alloy, used for hig wearh-resistance parts. Accept heat treatment to some 55 HRC.

            -630 (17-4PH) or (X6CrNiCuNb 17-04). Good mechanical characteristics. Good machine-ability and is the most corrosion resistant of all described. Harden by precipitation hardening to some 140kgs/mm² (43 HRC) at relatively low (500-600°C). Because of this  relatively low temperature , the 630is exempt of warping . This alloy would certainly be the most suited for the stainless receivers and bolts making

            R.G.C