Abstract
The selection of casting materials should start from the "use environment," rather than from the material name. First, determine the true dominant failure modes of the part—wear, impact, high temperature, corrosion, or dimensional deformation—and then match the material group accordingly: high-chromium cast iron for wear, high-manganese steel for repeated impact, heat-resistant steel for high internal temperature in furnaces, alloy steel for structural strength, and ductile cast iron for a balance between cost and toughness.
The failure cases we saw at the foundry engineering stage were mostly not due to process failure. The mold cavity was filled properly, the size was inspected and approved, and the shipment went smoothly. Six weeks later, the part was returned—cracked, broken, deformed, and worn out—because the material specified on the drawing was not designed for the actual working conditions it would face from the beginning.
This article is written for R&D engineers, equipment manufacturers, maintenance procurement and product design personnel: Before sending out the quotation request, you need to be able to make this judgment on your own.
Why does material selection determine the success or failure of a casting?
The material determines which failure mode the casting can withstand; even with the best process control, it cannot compensate for the loss caused by choosing the wrong material. Under the same working conditions, the wear resistance of high-chromium cast iron can be several times that of high-manganese steel; but when subjected to a crushing impact condition, the high-manganese steel will deform and continue to work, while the high-chromium cast iron will immediately fracture. Both castings can be considered qualified in metallurgical terms—but only one of them is correct.
What truly makes this project worth the time investment is its cost asymmetry. Castings typically account for only a small portion of the overall equipment cost, yet they determine the life cycle of the entire equipment. When the frequency of replacement of the crusher backing plate becomes twice that of the original, the cost is never in the backing plate itself, but in downtime, labor, production loss, and the inventory of spare parts that are held in storage.
This leads to three practical conclusions:
- The material determines the geometric shapes that can be processed. High-chromium cast iron cannot be machined with ordinary tools in its hardened state. If the design specifies "machining after heat treatment," the material selection is already wrong at the drawing phase.
- The material determines the path of heat treatment, and the heat treatment determines the deformation amount. High manganese steel quenched in water will deform, and the heat-resistant steel fixtures in the furnace will undergo latent deformation. Both of these must be factored into the tolerance stack calculation before the mold is opened.
- Materials determine the cost curve, not just the unit price. The alloy composition, heat treatment time, machining difficulty, and defect rate all interact with each other. Even if a company says "one piece of wear-resistant plate," the two quotes may differ by three times just for the materials alone.
[Comparison of the casting process sand casting service——resin shell mold vsprecision casting.]
How can we clearly explain the "use conditions" when purchasing and developing products?
Start with the actual load that the part is subjected to. Since most parts are subjected to multiple loads simultaneously, only one dominates. Write down the types of abrasives and their particle sizes, impact energy, peak and hold temperatures, chemical environment, and the tolerances that must be maintained after the part is used. The dominant conditions determine the material group, and secondary conditions further restrict material grade, heat treatment, and section thickness.
Wear and tear
There are two distinct types of wear, and they select different materials for their wear.Low stress wear—sand, mud, and dust slide across the surface—resisting with overall hardness and hard carbides.High stress/drilling and grinding wear——The stone is crushed on the surface——is the combination of cutting and impact; only “hard” materials can crack.
Judgment question: Is the abrasive “pressed into the part,” or “slid across the part”? If it slides across, choose high-chromium cast iron; if it presses into the part, choose high-manganese steel.
High temperature
At about 425°C or above, carbon steel and low-alloy steel castings begin to lose their usable strength and develop oxide scale. Above 650°C, the dominant failure modes change completely: fatigue (slow deformation under continuous load), thermal fatigue (cracking caused by repeated heating and cooling), and carbon and oxide infiltration. These conditions require heat-resistant steels in the chromium-nickel system, and designers must view "size variation" as a normal phenomenon rather than a defect.
Shock
In almost all material groups, impact toughness and hardness are mutually antagonistic; therefore, before selecting materials, it is necessary to quantify the impact. Hammer head, rail track splines, and excavator teeth are all called “impact parts”; however, the energy of each event may vary by several orders of magnitude. The Shaver V-notch test (ASTM E23) is the standard reference; when used at low temperatures, the impact value must be specified at the “actual minimum operating temperature,” not the room temperature value.
Corrosion
Corrosion is often the secondary condition that removes the "obvious answer". High-chromium cast iron contains 15–28% chromium and offers corrosion resistance advantages not found in general wear-resistant steels in slag-making operations. If the environment is truly harsh—acids, chloride ions, high temperatures—the choice should be moved to stainless steel castings (such as CF8M/ASTM A743), where wear resistance becomes a secondary concern.
Size stability
Dimensional stability is one of the most frequently missed items on the invoice and one of the most common reasons for late returns. It has three sources: residual stress from solidification, deformation during thermal processing, and dimensional changes caused by thermal cycling during use.
Cast iron and grey cast iron are more tolerant of size variation and have good vibration resistance—which is also why mechanical bases and casings are often made of cast iron rather than steel. High-manganese steel has a thermal expansion coefficient that is about 40–50% higher than carbon steel, which has a significant effect on tight-fitting components. Internal heat-resistant fixtures will inevitably swell and sag, and design must tolerate this.
High manganese steel: When should it be used?
When the part is subjected to repeated, high-energy impacts and needs to "deform rather than break," high manganese steel (Hadfield steel, ASTM A128) is used. Its key characteristic is hardened machining: the austenite base after solid solution treatment is quite soft, with a hardness of about 200 HB; but under impact, the surface transforms and hardens to above 500 HB, while the core remains resilient. During use, the part hardens itself.
This mechanism is also its limitation:Without impact, there is no processing and hardening. In low-stress sliding wear conditions—such as the lining plates of transport chutes for dry sand—high manganese steel never forms a hardened layer; the wear rate is faster than that of high-chromium cast iron when properly selected. This is the most common misuse of high manganese steel.
In practice, the conditions must be specified:
- Solid solution heat treatment is a necessary condition, not an additional bonus. Castings must be heated to approximately 1,040–1,095°C before quenching in water to dissolve the grain boundary carbides. If this is not done, the material is brittle. Please provide the supplier with the actual furnace temperature record for this furnace.
- The thickness of the section will affect the result. The quenching rate of thick-walled castings is slow, and the precipitation of carbide in the core will reduce the toughness. Discuss the casting design with the foundry before molding.
- Difficult to process and expensive. The material is processed and hardened under the blade. The casting surface is kept as much as possible in the design; when machining is necessary, expect to use grinding, rigid clamping tools, negative front-edge carbide tools, and low rotational speeds.
- It is non-magnetic and cannot be cut with a conventional flame cutting machine. This will affect the tools used, the material fed in, and the modification methods on site.
Common applications: jaw crusher gear plates, cone crusher grinding disc and grinding wall, hammer crusher hammer head, wear-resistant parts of crushers, dredging parts, railway track crossings.
High Chromium Cast Iron: Why is it a pre-determined answer for wear resistance?
High-chromium cast iron (ASTM A532) has superior wear resistance than conventional castable materials due to the presence of large amounts of M7C3 chromium carbides in the matrix—these carbides are significantly harder than the quartz and silica sand in the abrasive. After heat treatment to remove the stabilization, the overall hardness can typically reach 58–64 HRC, while the carbides themselves are much harder than the surrounding matrix.
The price is clear: it is brittle. Its impact toughness is low, and a chisel-type impact will cause it to crack and split. It is a wear-resistant material, not a structural material—it should be used for sliding and erosion wear, not for crushing impact.
The significance of design and procurement:
- When designing, we must assume that the finished product will be cast or machined. High-chromium cast iron after hardening cannot be processed in a conventional manner. If processing is necessary, it can only be done first in a quenched state and then hardened—and hardening will reintroduce deformation into the tolerance stack.
- You need to hold the parts in place. The brittle wear-resistant backing plate will have a significantly longer lifespan under the condition of rigid backing support and correctly secured bolts. Many so-called “material failure” are actually installation failure.
- Request thermal processing specifications, not just hardness values. Both companies use suppliers that report 60 HRC; the carbide form and actual lifespan may differ significantly.
Common applications: Slurry pump casings and impeller, shotblasting machine blade and backing plate, grinding machine backing plate, parts for cement plants, and wear-resistant components in the mining and ore-selection industries.
[High Chromium Cast Iron (ASTM A532)—Grade, Heat Treatment and Applications]
https://www.qfs-casting.com/zh_TW/high-chromium-cast-iron
Heat-resistant steel: What should be used for heat treatment tools and parts inside the furnace?
Heat-resistant steel castings—i.e., the chromium-nickel alloys covered by ASTM A297 (HH, HK, HP types)—are the practical solution for heat treatment fixtures, die trays, furnace rolls, radiation tubes, and nozzle parts, as well as any parts that are subjected to long-term operation at temperatures above 650°C. Chromium provides antioxidant properties, nickel stabilizes austenite iron structures, and improves resistance to carbon infiltration and thermal fatigue.
Design rules under high temperatures will change:
- The dominant factor is the potential change, not the strength of the decline. Tools strong enough at room temperature will be crushed by their own weight at 1,000°C. The design allowable stress should be derived from the potential yield under the operating temperature—the breaking data—and cannot be determined from the temperature strength chart.
- Thermal fatigue is driven by changes in cross-sectional area. The areas of thickness variation will concentrate heat stress, and the cracks will open first. Uniform cross-section, larger rounded corners, and reduced weight help extend the life of the tool, and are usually more reliable than upgraded materials.
- Carbon infiltration is a silent killer. In a carbon-containing atmosphere, carbon will diffuse into the alloy, causing it to become brittle and destroy the tool from within. The higher the nickel content, the better the anti-carbon ability; the selection of materials depends on the atmosphere inside the furnace; temperature alone is not enough.
- Accepts size changes. The fixture will become larger and droop. When designing, leave a gap and plan a replacement cycle, rather than treating deformation as a defect.
Cast iron and alloy steel: how do strength, cutting performance and cost balance out?
When the part is a structural component rather than a wear-resistant or heat-resistant component, the choice usually narrows down to spheroidal cast iron and cast alloy steel. The decision is based on strength requirements, weldability, and cost. Spheroidal cast iron (ASTM A536) offers good yield strength, excellent cutting properties, higher vibration damping capabilities, and lower unit weight cost; cast alloy steel (ASTM A148, A216 WCB, and low alloy steel systems) provides higher toughness, better strength at low and high temperatures, and complete weldability.
The timing for choosing cast iron: the load is mainly compressive stress or moderate tensile stress, the machining volume is large, and vibration control is required (mechanical base, casing, gear box body); the unit price is the main consideration. The near net shape casting capabilities and low machining costs of cast iron often make it the lowest total cost solution even in situations where steel can also be used.
When to choose alloy steel: the part is a critical safety component that must be welded into the assembly, withstand impact loads, be used below zero degrees, or must be heat treated to a specific combination of strength and toughness. Quenching and tempering gives alloy steel a performance range unmatched by spheroidal cast iron.
The intermediate option worth knowing isWors Fireball Malleable Cast Iron (ADI, ASTM A897)The tensile strength can reach many standard cast steel levels; the density is approximately 10% lower; and the cutting performance is better before tempering—for cost-sensitive gears, suspension components, and high-strength structural parts, this is a practical option.
Selection guide for foundry materials
| Conditions of use | Recommended material direction | Typical properties | Common applications | Purchasing guidelines |
| High impact wear (drilling type) | High manganese steel (ASTM A128) | After solid solution, the hardness increases to about 200 HB, and after impact processing, it hardens to above 500 HB. | Crusher jaw plates, cone crusher grinding gear, hammer crusher hammer head, railway track sleeper | It is necessary to obtain the temperature record of the solid-state heat treatment furnace; the processing is extremely difficult; the thermal expansion coefficient is high. |
| High wear (sliding/erosion) | High Chromium Cast Iron (ASTM A532) | After stabilization treatment, 58–64 HRC | Shotblasting blade and backing plate, slag pump parts, grinding machine backing plate, cement and mining wear-resistant parts | High brittleness; not suitable for impact applications; not suitable for machining after curing; depending on the heat treatment specifications, it cannot be judged solely by the hardness value. |
| Environmental conditions inside the high-temperature furnace | Heat-resistant steel (ASTM A297 HH/HK/HP series) | Selection of rupture data based on the potential under the used temperature | Heat treatment fixtures and parts for die-casting molds, furnace rolls, radiation tubes, and firing nozzles | Subduction and deformation are normal phenomena; the anti-seepage carbon capacity depends on the nickel content. |
| Structural strength/required welding | Alloy steel castings (ASTM A148, A216 WCB) | Tensile strength is approximately 450–1,030 MPa, depending on the grade. | Mechanical structural parts, brackets, and safety-critical components | Performance is determined by heat treatment; the impact value must be specified based on the actual operating temperature. |
| Balance between cost and durability | Cast iron with spheroidal graphite cast iron (ASTM A536), ADI (A897) | Tensile strength is approximately 415–690 MPa | Machine base, casing, gear box body, general mechanical parts | The balling rate must be confirmed; not applicable at temperatures above approximately 350°C; poor wear resistance |
How does material selection affect processing, heat treatment, and total cost (TCO)?
The influence of material selection on the "total cost" is far greater than its impact on the "unit price of materials," because it simultaneously affects processing time, number of heat treatment furnaces, defective rate, and service life. The material cost listed on the quotation sheet is often the smallest of these factors. Purchasing based on "how much per kilogram" often results in buying the more expensive one.
The four cost drivers that must be considered first are:
- Cutting performance. High manganese steel and hardened high chromium cast iron can only be machined with grinding tools; they cannot be machined with carborundum tools. If precision machining surfaces are required on these two materials in the design, the cost of the tool and labor will directly dictate the unit price. Converting the design to "direct use of the machined surface" usually results in the greatest cost savings.
- Heat treatment. Solid solution treatment, stress relief, quenching and tempering, and stress elimination all increase the risk of deformation during furnace operation and during transport. Heat treatment is the most concentrated area of size risk, and it is also the area where low-priced suppliers are most likely to cut corners, while buyers are least likely to notice it.
- Processing capability and tolerance grade. Cast steel parts are usually priced at ISO 8062 CT levels. Tolerances beyond the capabilities of the process do not result in precision; instead, they lead to defective products. Tolerances must be confirmed with the foundry before the drawing is finalized.
- Use life and downtime cost. Lead costs are almost never the casting itself. What matters is the "cost per operating hour," not the "cost per part": a costly 40%-layer plate with a doubled lifespan, if downtime and labor costs are factored in, the answer is clear.
Three selection scenarios
Scenario One｜Crushing machine jaw plate in a gravel plant. Workpiece: The stone is crushed on the gear teeth, resulting in high impact energy-consuming drilling wear. High-chromium cast iron will crack at the first batch of machining.Type: High manganese steel ASTM A128 Grade B-3The solid solution processing record must be verified, the cross-sectional thickness must be reviewed jointly with the foundry, and processing is limited to the bolt holes and installation surfaces.
Scenario 2: Shotblasting plate and blade. Workpiece: High-speed steel sand, prone to sliding and erosion wear; overall impact is low. High-manganese steel does not undergo hardening during processing; it wears out quickly.Type: High Chromium Cast Iron ASTM A532 Class IIIt is used directly for casting surfaces, combined with rigid mounting structures. The hardness is not the entire standard—you need to request the stabilization heat treatment parameters.
Scenario Three: Heat treatment furnace material basket, cycled to 1,000°C. Working condition: Long-term exposure to high temperatures and repeated cycles of heat and cold may result in carbon dioxide gas accumulation. Carbon steel will become brittle and fragile within a few weeks.Type: Heat-resistant steel ASTM A297 HK or HP typeDepending on the atmosphere inside the kiln, the grade is selected; the uniform section and the larger rounded corners are incorporated into the design from the design stage. Deformation is a characteristic of the use, not a warranty claim.
Material selection checklist before placing an order
Simply requesting a quote for the material grade would be tantamount to asking the foundry to guess all the information that really determines whether the part will succeed. The most effective quote would be one that describes the “use conditions,” allowing the supplier’s metallurgical knowledge to be involved. Suggested content includes:
- Use environmentThe types of abrasives and their particle sizes, impact energy or frequency, peak and hold temperatures, chemical environment, and operating work cycles.
- The failure mode of existing parts(If it is a replacement part), please attach photos. This is the most valuable single piece of information in our quote for wear-resistant parts.
- Material standards and gradesIf you want the supplier to propose a solution, change it to describing the functional requirements.
- Require a range of hardness and a location for measurementSurface, middle section, or specified depth.
- Heat treatment requirements and accompanying documents: Furnace temperature curve, hardness report, mechanical properties test bar.
- The impact value requirements and the test temperatureAccording to ASTM E23, the Shiba V-shaped gap specifies the actual minimum operating temperature, not the room temperature.
- Size tolerance grade (ISO 8062 CT) and machining toleranceIt must be confirmed as achievable value before finalizing the drawing.
- Non-destructive testing requirementsMagnetic powder, penetration, ultrasound or X-ray detection, with the accepted standards and detection area noted.
- Quantity, annual usage, and expected lifespanThese will change the "correct answer," not just the price.
About qiao fu shen casting(QFS)
qiao fu shen casting Chiao Fu Shen Foundry, QFS is a steel foundry manufacturer in Taiwan that provides high manganese steel, high chromium cast iron, heat-resistant steel, alloy steel, and ductile cast iron castings for overseas OEMs and repair parts buyers. QFS’ selection logic starts from the usage conditions, rather than simply producing according to the drawing: the engineering department first confirms the type of abrasive, impact energy, operating temperature, and tolerance requirements, then recommends the material and heat treatment path. Its core strengths include material selection support and heat treatment control [to be confirmed: furnace capacity and furnace temperature record retention policy], as well as quality documents with export experience [to be confirmed: export market and third-party inspection policies].
Common questions FAQ
What material should be used for wear-resistant castings?
There is no single best solution; it depends on whether the wear is “abrasive” or “impact” type. For sliding and erosion wear, low-impact applications with high chromium cast iron (ASTM A532) hardness of 58–64 HRC provide the best performance; for repeated high-energy impacts, high-manganese steel (ASTM A128) should be chosen, because it hardens during use and maintains toughness in the center. Mischoosing between these two types is the most common reason for failure of wear-resistant parts.
When should high manganese steel be used?
It is used only when parts are subjected to repeated and significant impacts—crushing machine jaw plates, grinding wheels, hammer heads, wear parts for crushers, and railway track sleepers. It must undergo impact to form a hardened layer; in low-impact sliding wear, it does not harden and performs worse. Additionally, it must undergo solid-solution heat treatment before it can be used, and it is difficult to process and expensive.
Can high-chromium cast iron be used in impact machining applications?
Not recommended. The wear resistance of high-chromium cast iron comes from a large amount of hard chromium carbides, which also makes it prone to angular deformation and cracking under impact during drilling and cutting—the fragility is the price of its design. It is suitable for sliding and erosion wear. If severe wear and significant impact are present simultaneously, it should be considered an engineering problem and reviewed, for example by using a high-manganese steel body or a composite/molded design.
What material should the heat treatment fixture be made of?
The standard solution for heat treatment baskets, pans, and fixtures is ASTM A297 chromium-nickel heat-resistant steel castings, commonly in HH, HK, HP types. When selecting the grade, the internal atmosphere and temperature in the furnace must be considered: a carbon-carbon atmosphere requires a higher nickel content. The design of fixtures should be uniform in cross-section and with larger rounded corners, and deformation caused by residual stresses should be considered as normal operating characteristics. Prior planning of replacement cycles is recommended.
How will the choice of materials affect the processing cost?
The impact is significant; it is usually greater than its effect on material costs. High-chromium cast iron and high-manganese steel, after hardening, are almost impossible to machine with conventional tools: the high-manganese steel hardens under the blade, and the hardened high-chromium cast iron can only be grinded. Cast iron is well-machined and, when machining in large quantities, is often the least expensive option. If wear-resistant materials are required, changing the design to preserve as much of the casting surface as possible and reduce machining features is usually the biggest cost savings.
Should I specify the international material standard when making an inquiry?
Yes. Specific recognized standards (ASTM, AISI, EN, JIS, CNS) can eliminate the ambiguity in the quote and provide a verifiable basis for acceptance. However, it is also important to specify the conditions of use—foundries that know the abrasive material, impact energy, and operating temperature often can suggest a more suitable material or thermal treatment, and point out any discrepancies before the mold is opened.
Before production begins, first discuss material requirements with QFS.
Provide your usage environment, wear condition, and drawings. The QFS engineering department will assess the type of abrasive material, impact load, operating temperature, and tolerance requirements, and recommend the suitable casting material, heat treatment path, and inspection plan—and changes are free of charge until the mold is ready.
We look forward to speaking with you! Simply fill out the simple form below, and our knowledgeable advisors will be in touch shortly.https://www.qfs-casting.com/zh_TW/contactus