Heat Resistant Alloys

CASTALLOY TECHNOLOGY CORPORATION produces a wide range of replacement parts in a variety of alloys to suit the needs of the cement plants and associated industries. Our casting products meets the two basic requirements :

  • Surface Film Stability, which includes “oxidation” and “corrosion resistance” in various atmospheres within the temperature range of operation.
  • Mechanical strength and ductility for the service requirements

We have recommended the following composition material to be used in different surrounding temperature :

  • CASTALLOY 4HR1 ( Nearest equivalent : DIN 1.4710 ) and CASTALLOY 4HR2 ( Nearest equivalent : DIN 1.4059 ) type iron chromium alloy castings containing 16% to 18% chromium. These alloys are used for resistance to oxidation since they posses relatively low strength at elevated temperatures. The chromium content is increased as the service temperature increased. These alloys are ferric and magnetic.
  • CASTALLOY 4HR3 ( Nearest equivalent : ACI-HF ) is an iron - chromium – nickel alloy similar to the well known type corrosion resistant composition   (18Kr, 11Ni) but containing somewhat more chromium and nickel, and substantially more carbon. The increased chromium content confers added resistance to oxidation at elevated temperature, and the higher nickel and carbon levels ensure an austenitic structure. Accordingly, this grade is suitable for applications requiring high strength and corrosion resistance ranging from 1200°F to 1600°F. It is in oil refinery and heat treating furnaces.

As a cast, the alloy has an austenitic matrix containing interdendritic eutectic carbides and occasionally an unidentified lamellar constituent. Aging at service temperature is usually accompanied by precipitation of finely dispersed carbides resulting in a higher room temperature strength and some loss of ductility. Improperly balanced alloys may be partially ferritic as a cast, and such material is susceptible to embrittlement from sigma phase formation after long exposure at 1400ºF to 1500ºF.

  • CASTALLOY 4HR5 ( Nearest  equivalent to ACI HH-1 )  and  CASTALLOY 4HR6   (Nearest Equivalent to ACI HH-2) is an iron – chromium – nickel alloy containing 24% to 26% chromium and 13% to 14% nickel, with chromium always exceeding nickel content. These alloys are partially or fully austenitic, and have greater strength and ductility in service than the iron – chromium group. These alloys can be used in sulfurous, oxidizing and reducing atmospheres.
  • CASTALLOY 4HR7 ( Nearest equivalent : ACI – HI type 26-28 Cr, 14-18 Ni ) with higher nickel and chromium content than type 4HR5 and 4HR6. More resistant to oxidation and can be used up to 2150ºF, though similar to 4HR7 & 4HR8 in composition sensitivity and mechanical properties, it is austenitic. Cast returns for magnesium production has been a major application for this grade.
  • CASTALLOY 4HR8 ( Nearest equivalent : ACI–HK type 24-26 Cr, 18-20 Ni ) has higher nickel content than 4HR5. This alloy has high strength and temperature above 1700ºF, and can be used in structural applications up to 2100ºF. It resists hot gas corrosion better than 4HR6 and 4HR5 and is not recommended for higher sulfur atmosphere, or where severe thermal shock is a factor.

It is widely used for parts where high creep strength is needed, such as :

  • Jet Engines
  • Gas Turbines
  • Hydrogen Reformer Tubes
  • Furnace Parts
  • Chains

 

Comparable Compositions

Chemical Compositions

 1%-1000h – CREEP Unit in = N/mm² AT

Return to Top      

 

  Abrassion Resistant Alloy Steel

CASTALLOY CA2HSWAR1C4, CA2MWAR4C8 Pearlitic Chromium Molybdenum Steel

High – Carbon Pearlitic Chromium – molybdenum steel castings with hardness range of 280 to 450 BHN were used in many years for cement plants and associated industries, including ball and rod mill liners, grates, and other abrasion – resistant castings.

Actual composition and heat treatments were varied depending on preferences of the supplier in a specific operating conditions. The preferred compositions ranges and heat treatments which has been a general use after years of experience, are given below :

Typical Application :

  • CASTALLOY 2HSAR1 – Ball mill grates, clamp and ball mill liners exposed to high impact conditions.
  • CASTALLOY 2MIWR4 – Ball and rod-mill liners, chute liners exposed to lower low impact conditions.

Return to Top      

 

  Wear Resistant Chrome-Moly Alloy Steel

CASTALLOY 3HWAR2 is a chrome-moly white iron alloy predominantly used in cement, clinker, limestone, marble, gypsum, and many other materials being crushed. The most common of this alloy are recommended for wear elements, usually a Roller Tyre mounted on a stationary arm with a driven track rotating beneath the arm causing the roller to rotate.

Long service life for the wearing components is as necessary as cost of taking mills out of service for repair and maintenance. It is usually considered essential to select the most abrasion resistant material available, regardless of cost. CASTALLOY TECHNOLOGY Corporation offers a range of proven high chromium iron materials which gives the benefit of long life without incurring a cost penalty. Conforming to BS, ASTM, and DIN specifications but with tighter metallurgical and heat treatment controls, these alloys are superior to more traditional materials such as NiHard. They are harder and tougher and up to a 100% increase in component life has been achieved many times in well-documented field trials.

The increase in life associated with the high chromium family of iron stems from metallurgical structure of the material in which chromium carbides are embedded in a matrix material. This matrix can be altered in toughness and hardness by heat treatment or alloying elements to suit the particular service environment. Chromium carbides are significantly harder than the iron carbides usually found in wear resistant materials.

Each selections reflects component size, impact conditions, abrasive nature, and grindability of the material and the production cost of the component, all with a view to providing a true cost effective solution to any abrasion problem.

Among the facilities offered by CASTALLOY, is a quality control commitment which for certain components includes three separate dye penetrate crack detection procedures, complete machine shop using the latest in modern cutting technology and design section where operating results matched with material selection and component geometry to give optimum performance.

Design Engineering is an important part of CASTALLOY TECHNOLOGY Corporation’s operation. The engineering staff, working in conjunction with customer maintenance sections, pioneered the development of profiled roller cast in a geometry to suit the eventual table wear pattern and to enhance both roll table life.

A major benefit arising from the use of high chromium iron is that, the component will have a consistent hardness through its cross section.

Components for the wear parts of vertical spindle mills can weigh by several orders of magnitudes. Thus a thick section roller weighs less than a 100kg. The response to a given heat treatment cycle would be different as would the nature and magnitude of the forces acting on the component in service.

For the above reasons, CASTALLOY TECHNOLOGY Corporation adapts the philosophy of tailoring individual alloys to the specific applications being considered.

 

ALLOY NOMINAL CHEMICAL COMPOSITION

Return to Top      

 

  High Strength Steels & High Impact Resistance Steel Alloys

The ability of austenitic manganese steel to absorb shock (impact ) is taken into consideration. This table refers to the applications in the mining and quarry industry.

Austenitic Manganese Cast Steels Ability for Wear Resistance

    * are alloys which might not have sufficient toughness.

CASTALLOY 2HSAR3, 2HSAR2, and 2HSAR4 – These are austenitic manganese steel and are sometimes referred to as Had fields Manganese Steel after its inventor, and is also often spoken of “High Manganese Steel”. This steel of low strength, high ductility, tough, non-magnetic steel capable of developing excellent wear resistance when surface hardening by cold working.

The composition of austenitic manganese steel, as usually produced to ASTM Standard A128 Grade A, is within the following limits :

Return to Top     

 

 


© 2001 Castalloy Technology Corporation. All rights reserved.