Refractory stainless steel
Below is an overview of materials used in anchoring elements. They differ in resistance to temperature, corrosion, sulphuric environment and other properties. We use these alloys to manufacture our anchoring systems and we also sell them as raw material.
AISI 304 (1.4301)
AISI304 is the most common alloy used in stainless steel anchors. It is a general purpose alloy suited for a variety of corrosion resistant applications. We recommend it for use in applications involving constant temperatures of up to 750 °C (significant thermal cycling may cause embrittlement).
AISI 309 (1.4828)
The AISI 309 alloy has a characteristically low nickel content and a relatively high chrome content. The low nickel content means that this alloy can still be used effectively in environments where sulphur is present. It offers good stability and is suitable for use in temperatures of up to 1,000 °C. We recommend it for applications involving constant high temperatures.
AISI 310S (1.4845)
This is a very popular alloy type in our industry, with good strength and oxidation resistance. Even though it is susceptible to Sigma precipitation, it is resistant to thermal cycling and oxide spalling damage, especially in environments with high gas velocity. With CUPLOCK, anchors made of this alloy may be used in temperatures of up to 1,200 C° and are especially suitable for gas kilns.
AISI 310 (1.4841)
This alloy has the same properties and specifications as AISI 310S, but a higher carbon content (max. 0.25). This alloy steel is frequently used as a standard anchor material for applications involving high temperatures. It has good thermal and corrosion resistance and may be used in temperatures of up to 1,150 °C. It is suitable for applications with constant temperatures.
AISI 330 (1.4864)
This alloy is able to withstand temperatures of up to 1,250 °C in oxidising environments. It is suitable for metal annealing furnaces, where thermal cycling occurs. It has good strength and thermal shock resistance. This alloy is not suitable for applications involving sulphuric environments, but excellent for low-oxygen environments. It has good carbon and nitrogen absorption resistance and is a good alternative to Inconel 601, especially for heavy refractory anchors. Together with lock washers, this alloy is equal to or superior to Inconel 601 as a result of its higher melting point (1,400 °C).
The DS is similar to AISI 330 and is suitable 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 immune against formation of sigma phases as a result of its composition, so it can also be used in systems that are operated in cycles. The DS alloy is often used as a replacement for AISI 330, because it is readily available on the market.
253 MA (1.4835, 1.4893)
This steel is based on the 309 alloy, with small additions of rare earth elements, which give it excellent oxidation resistance in temperatures of up to 1,150 C°. It is suitable for continuous high temperature applications demanding slightly better performance than type 310 AISI.
This alloy is especially suitable for applications involving high temperatures, especially those above 1,250 °C. It is immune to Sigma formation and great for thermal cycling and thermal shock applications. Compared to other alloys, Inconel 601 offers superior strength and is therefore suitable for heavier refractory in temperatures above 1,150 °C.