Alloys

Alloys - Selection of alloys | vhi

Selection of alloys

With the increasing stresses placed on refractory linings and thus on the metal anchors which support them, in the form of high temperatures, chemical attack by hot gases or, on cooling below the dewpoint, attack by aggressive aqueous solutions, etc., selection of the right anchor material is not always simple. With its long term experience our staff will be glad to support clients.

The selection of a suitable alloy should not be based on individual criteria; rather the different requirements should, where possible, result in a comprehensive assessment so that the correct decision can then be made for the specific application.

1.4301 (vhi 304)

The austenitic 1.4301 is a widely distributed type of alloy with diverse uses. When used at temperatures from 700 - 750° C it has good temperature and intercrystalline resistance to corrosion. This alloy is well suited to use at constant temperatures. Strong temperature cycles can cause or emphasize signs of embrittlement.

1.4828 (vhi 309)

The low nickel content in the composition with relatively high chrome content is characteristic of 1.4828. The low nickel content means that this alloy can still be used effectively where sulphur attacks are to be anticipated. The 1.4828 has good stability and is suitable for use at temperatures of up to 1,000° C. Due to its composition, 1.4828 should not be used in units that are operated in cycles because it is sensitive to sigma phase embrittlement. 1.4828 is extremely suitable for use at continuously high temperatures.

1.4893 / 1.4835  (vhi 253)

In terms of basic composition, the material 1.4893 / 1.4835 is very similar to 1.4828. Alloys with rare earths and nitrogen make this alloy superior to 1.4828. In addition to the scaling temperature in air of 1150°C, the stability and creep strength are also improved. The alloy 1.4893 / 1.4835 is characterised by excellent resistance to high temperature corrosion in most atmospheres.

1.4841 (vhi 314)

This alloy is frequently used at high temperatures as a kind of standard tool for anchoring. 1.4841 has good properties both when it comes to heat properties and to corrosion resistance, and can be used up to approximately 1150° C. As with the material 1.4828, 1.4841 is very prone to sigma phase embrittlement and should therefore where possible be used as anchoring material in continuously operated system components.

1.4845 (vhi 310)

1.4845 has the same properties and technical data as 1.4841, but has an advantage in terms of the sigma phase embrittlement. Due to the very low proportion of silicon (maximum of 0.75%) in the composition, precipitation to the sigma phase is temporally delayed and reduced in quantity.

1.4862 (vhi DS)

1.4862 is the suitable alloy for anchoring systems that are to be used at high temperatures, especially under strongly carburised or nitrating conditions. With good stability values, this alloy is completely protected against the formation of sigma phases due to its composition, so that it can also be used in systems that are operated in cycles.

2.4633 (vhi 602)

Alloy 2.4633 is the right choice for the most demanding requirements, both in terms of the application temperature and the corrosion resistance. The addition of aluminium to the alloy drastically improves the heat properties. All in all the material has very good oxidation resistance also under cyclic conditions, excellent corrosion resistance against carburised, oxidising/chlorinated media as well as outstanding creep resistance.

Other alloys

vhi has other alloys for specific requirements and which are suitable for certain requirements. We are happy to advise you in this respect.