The PN-86/H-85021 standard, " Alloy tool steel for hot work – Grades," is a Polish standard specifying requirements for alloy tool steel intended for use at high temperatures, also known as hot work steel. The document specifies the chemical composition, mechanical properties, heat treatment processes, and applications of these materials, ensuring uniform quality standards for tools used in metal forming.
Standard PN-86/H-85021 Hot work alloy tool steel – steel grades covered by the standard:
The PN-86/H-85021 standard covers various grades of tool steel, including:
- WCL (1.2343, X37CrMoV5-1) – steel with high hardenability and tempering resistance, used, among others, for die inserts and casting dies.
- WCLV (1.2344, X40CrMoV5-1) – a variety with the addition of vanadium, increasing wear resistance and temperature stability.
- WNL (1.2713, 55NiCrMoV6) – steel intended for forging dies and tools for forming non-ferrous metals.
- WWV (1.2581, X30WCrV9-3) – steel with high impact strength and temperature resistance.
- WWS1 – used in extrusion presses and forging dies.
Each of these species is characterized by specific properties that determine their purpose in various industries.
Application:
Steels covered by the PN-86/H-85021 standard Alloy tool steel for hot work – grades are widely used in the production of tools exposed to intense thermal and mechanical conditions, such as:
- Forging dies.
- Casting molds for light metals.
- Punches and die inserts for presses.
- Hot cutting knives.
Their properties, such as tempering resistance, high hardenability and strength at elevated temperatures, ensure long-term tool durability and work efficiency.
Standard PN-86/H-85021- Hot work tool steel – species - heat treatment:
The standard also describes heat treatment processes designed to achieve optimal mechanical properties of steel. Requirements include hardening, tempering, and soft and stress-relieving annealing, tailored to the specific characteristics of each grade.
The PN-86/H-85021 standard provides a comprehensive standard for hot-work tool steels, ensuring uniform and high quality requirements across the tool industry. Thanks to this, manufacturers and users can count on materials with consistent properties that ensure reliability under demanding operating conditions.
The PN-86/H-85021 standard Hot-work tool steel was replaced by the PN-EN ISO 4957:2002 standard , which entered into force on August 15, 2002. Officially, the PN-86/H-85021 standard was withdrawn on April 13, 2004.
Subsequently, the PN-EN ISO 4957:2002 standard was updated to PN-EN ISO 4957:2004 , and later by PN-EN ISO 4957:2018-09 , which has been in force since 13 September 2018. PN-EN ISO 4957 is the current standard for tool steels, including hot-work steels.
The new standard introduces harmonized requirements at European and international level regarding the chemical composition, mechanical properties and test methods for tool steels, ensuring consistency and uniformity of standards in European Union countries.
The PN-EN ISO 4957 standard is more rigorous and comprehensive compared to PN-86/H-85021 for several reasons:
1. International scope and harmonization:
- PN-EN ISO 4957 is an international standard, harmonized throughout Europe and consistent with global ISO standards.
- PN-86/H-85021 was a national standard, adapted mainly to the Polish industrial realities of the 80s.
2. Chemical composition accuracy:
- ISO 4957 defines more precise permissible deviations of chemical composition, which translates into better quality control and material repeatability.
- PN-86/H-85021 had less detailed guidelines regarding chemical composition tolerances.
3. Mechanical properties and tests:
- ISO 4957 introduces more stringent requirements for mechanical properties such as hardness, tempering resistance and heat resistance.
- PN-86/H-85021 focused mainly on basic parameters without such precise quality tests.
4. Research methods:
- ISO 4957 specifies detailed procedures for testing mechanical properties such as impact, hardness and microstructure tests.
- PN-86/H-85021 had a more general approach to research methods.
5. Heat treatment:
- ISO 4957 provides more detailed recommendations for heat treatment, including hardening, tempering and cooling temperatures.
- PN-86/H-85021 gave general temperature ranges without such detailed guidance.