ISO/TC 226/WG 1 - Carbonaceous binders, including pitch

This document specifies the ring-and-ball method, a method of using the ring-and-ball apparatus for the determination of the softening point (softening temperature) of pitch used in the production of aluminium. The method is applicable to pitches having softening points equal to or greater than 30 °C.

ISO 5940-2:2007 specifies a method to determine the softening point of pitches by the Mettler method, within the range of 50 °C to 180 °C. It can be used for other organic materials that are used as binder and impregnating agents, where they have a Mettler softening point within the range of 50 °C to 150 °C.

This International Standard describes a method for determining the sulfur content of pitch used in the production of aluminium. The method is applicable to pitches of both coal tar and petroleum origin, provided that they contain between 0,1 % and 4,0 % by mass of sulfur.

Specifies a method using a disc-shped test piece to be prepared by moulding a test portion ina ring which is fitted into a heated bath. A steel ball is placed on the upper surface of the test piece. Then the temperature (softening temperature) is determined at which the test piece, on heating at a prescribed rate, softens sufficiently to sag to a specifeid depth under the mass of the ball. Details on the thermometers to be used and information on the melting of pitch samples are included in two annexes.