How to Select the Right Tool Steel for Mold Cavities
With cavity steel or alloy selection, many variables can dictate the best option. Things that need to be considered are the material you’ll be molding, cycle-time expectations, part criteria, expected volume, tooling costs, and maintenance. The goal here is not to suggest, recommend, or give preference to any specific steel or alloy, but to offer some guidance you should take into account when making the selection.
YK30 (SK3) carbon tool steel, grade T10A.
Uses： Stripping, up and down pads, splints with higher requirements, female and male molds with lower requirements.
Mechanical properties: heat treatment quenching temperature 760°, return water temperature 140°~250°, hardness HRC50°~58°.
D3, alloy tool steel, grade C12.
Uses： Stripping, underlaying, female and male molds with lower requirements.
Mechanical properties: heat treatment quenching temperature 950°~980°, return water temperature 180°~250°, hardness HRC50°~56°.
SKD11, grade CR12M0V
Uses： Male molds, female molds, and molds with higher requirements, such as stripping of continuous molds of stainless steel shrapnel, etc.
Mechanical properties: heat treatment quenching temperature 980°~1050°, return water temperature 180°~250°, hardness HRC 55°~62°.
DC53 (SKD upgrade product)
Uses: Commonly used in male and female molds of higher density molds.
Mechanical properties: Hardness and wear resistance are better than SKD, deformation coefficient is less than SKD. Heat treatment quenching temperature 980°~1050°, return water temperature 180°~250°, hardness HRC55°~62°.
High-speed SKH-9, grade W6CrM05V2
Uses： It is often used in the master block (insert) of engineering molds or continuous molds and punches for punching small holes. Many tools such as ordinary milling cutters, drills, wiretaps, etc. are also suitable.
Mechanical properties: high hardness, good wear resistance, complicated heat-treatment process. Hardness HRC62°~64°.
NAK80, pre-hardened Die steel.
The electrical processing performance is good, the mechanical processing performance is poor, and no heat treatment is required after processing. Due to the compact internal molecular structure of the material, the polishing performance is good.
SS41 (also known as A3 steel) is a carbon structural steel.
Uses： upper and lower mold seat feet, heightening boards, supporting boards, lower backing boards, splints.
Gray cast iron (pig iron), a commonly used grades of gray cast iron HT30~54.
Uses Mould base, general machine bed.
45# steel is a high-quality carbon structural steel.
Uses： Commonly used as a material for shaft parts.
Mechanical properties: good mechanical processing performance and strong hardness, quenching and tempering treatment, quenching temperature 820°~850°, return water temperature 600°~650°, HRC40°.
There are pros and cons to each option, so it’s important to know all the angles to understand the long-term cost versus just the up-front tooling costs. If you need wear-resistant steel, you are looking at hardened tool steel. This will increase your tooling costs upfront but will reduce your maintenance costs in the long term. But here’s the twist: Hardened steels are less thermally conductive, which can impact cooling time if you don’t put extra focus on the tool design for cooling. If you go with standard tool steel that will not be hardened, your cost will be lower upfront but your long-term maintenance cost will be greater.
Tool steel is an essential material used in the manufacturing of molds for various applications. Choosing the right tool steel is crucial to ensure the mold cavity’s durability, longevity, and performance. Here are some factors to consider when selecting the right tool steel for mold cavities:
Material being molded: The material being molded has a significant impact on tool steel selection. Different materials have varying levels of abrasiveness and corrosiveness, which can affect the mold cavity’s surface finish and lifespan. For example, molding abrasive materials like glass-filled plastics require a tool steel with high wear resistance.
Mold size and complexity: The size and complexity of the mold cavity also play a role in tool steel selection. Large molds require a tool steel with high toughness and strength, while complex molds with intricate details need a steel with excellent machinability.
Production volume: The production volume of the mold cavity also affects tool steel selection. High-volume production requires a tool steel with high wear resistance and toughness to withstand the constant use and minimize downtime.
Mold temperature: The mold cavity’s operating temperature is another critical factor in tool steel selection. High-temperature molding applications require a tool steel that can withstand thermal fatigue and maintain its mechanical properties at elevated temperatures.
Cost: The cost of the tool steel is also an important consideration, as it can significantly impact the mold’s overall cost. Balancing the cost with the desired properties is critical to achieve the best value for the mold cavity.
In summary, selecting the right tool steel for mold cavities involves considering the material being molded, mold size and complexity, production volume, mold temperature, and cost. By considering these factors, you can choose a tool steel that meets your requirements for durability, performance, and cost-effectiveness.
