We, LAWAI INDUSTRIAL CORPORATION produces heat-resistant steel tubes by centrifugal casting technique in Taiwan. The heat-resistant steel tubes applied in heating furnaces are called radiant tubes. And the materials of radiant tubes could be HU , HP…etc.  In this article, we would like to introduce the characteristics of the heat-resistant steel we produce often and why centrifugal casting is a very good technique to produce heat-resistant steel tubes. 

Custom heat-resistant steel tubes production - HK , HK40, HF,  HT, HU, HH and HP tubes

HK, HK40, HF, HT, HU, HH and HP tubes are the heat-resistant steel materials we produce them by custonmer's demands often and the characteristics of these alloys are as follows. 

HK tubes and HK40 tubes 

HK tubes are with higher strength and oxidation resistance.  The HK tubes are able to be used under the temperature that reaches 1038 °C(1900 °F). These materials are suitable for being applied in the petrochemical industry as catalyst tubes, pyrolysis tubes ,radiant tubes and so on. 

HF tubes 

HF tubes are with good corrosion resistance and mechanical properties under 816°C(1500°F).  HF alloy is similar with HH alloy on several aspects.  HF tubes have the moderate strength and ductility.  HF alloy is good for being the material of furnace tubes and fittings. 

HT tubes

HT tubes are with excellent resistance of thermal shock, thermal fatigue and carburization.  HT is the popular material at the foundries because of its feature of thermal shock resistance.  Under high temperature, HT alloy performs the good oxidation and carburization resistance.  HT alloy is as the material for furnace tubes used in heat-treatment industries usually. 

HU tubes

The strength of HU tubes increases when the temperature goes up.  HU tubes have the good corrosion resistance for the gases with sulfur.  HU tubes are with high creep resistance and ductility both when the temperature reaches 1093°C(2000°F).  Once there is the demand of the tubes with high strength under high temperature, HU alloy is able to be considered.  HU alloy is usually applied in the environment with high pressure and rapid thermal cycle such as heat-treatment industry.  

HH tubes 

HH tubes are with good strength and oxidation resistance during 760~982 °C(1400~1800°F).  HH alloy is well-known heat-resistant steel material.  It contains the minimum Cr and Ni, but it shows the high corrosion resistance and strength on 871°C(1600°F).  HH alloy is divided to two types- HH type 1 and HH type 2.  HH types 1 is used in the environment that ductility is more important.  However, HH type 2 is applied in the environment with stress load. 

HP tubes

When HP tubes are applied in the condition with high temperature, they perform oxidation and carburization resistance.  HP is related to HN and HT.  HP alloy is with higher Ni than HN and with higher Cr than HT.  This composition makes HP alloy be with oxidation and carburization resistance during 982~1093°C(1800~2000°F) and be with the resistance of high stress rupture.  HP alloy is usually used as the material for catalyst tubes in petrochemical industry and furnace tubes in heat-treatment industry. 

Heat-resistant steel tubes are divided into two groups- Resisting stress and non-resisting stress tubes

Radiant tubes and rolls we manufacture often are non-resisting stress tubes.  And these tubes are used in heat-treatment and steel industries.  

The typical resisting stress tubes are catalyst tubes and other tubes of gas transformers in petrochemical industry.  The heat-resistant steel tubes with stress resistance have small diameters and longer lengths( almost over 4 meter).  It is more difficult to produce these tubes and the final inspection is also complicated.  Therefore, we regard the tubes as higher grade centrifugally cast tubes.  

Developing the heat-resistant steel tubes with stress resistance is our goal.  We have the strong intention to supply the tubes to our local petrochemical plants.  800H is one of the materials of catalyst tubes and this alloy was developed successfully at LAWAI. 

Centrifugal casting is the techniaue suitable for producing heat-resistant steel tubes

Centrifugal casting is very suitable for producing heat-resistant steel tubes because it makes tubes by high speed rotation instead of solid metal formation. 

Heat-resistant steel is high carbon content that is "not" good to be produced(formed) by rolling and extruding. 

LAWAI INDUSTRIAL COPR. produces stainless steel and heat-resistant steel tubes by centrifugal casting 

In addition to HK, HK 40, HF, HT, HU, HH and HP tubes, other heat-resistant steel such as HP-MOD and 800H are able to be produced by us.  We do the evaluation based on the chemical composition and the dimensions of the tubes customers provide.  The minimum thickness of heat-resistant steel tubes is around 4.5~5 mm and we will propose the best suggestion based on the working environment to meet customers’ expectations.

If you have the demands of heat-resistant steel tubes manufactured by centrifugal casting technique, please contact us via email.

[email protected]