Metrode Ultramet-R1738H description: Thermet R17.18H is designed to match fully austenitic high alloy heat resisting steels often called 17/38 or 38/17. Alloys of this type are produced as castings with about 0.4%C, or in wrought form with carbon of about 0.08%. Thermet R17.38H matches the composition of castings but experience has also shown it to be compatible wit the wrought alloys, although higher weld metal ductility will be obtained with a nickel base type (data sheet D-11). The high nickel content and low thermal expansion of the alloys give good resistance to thermal shock. The alloy is also highly resistant to carburisation and oxidation but is not suitable for use in high sulphur bearing atmospheres.