Sub-zero tempering (TEAR)

Suitable for tool steels and some engineering steels where extra-dimensional and microstructural stability is required.


  • Increased hardness and strength.

  • Improved long term dimensional stability and wear resistance.

Technical specification

A process used to complete phase transformations and improve dimensional stability performed as a sub-zero tempering cycle after hardening.

A component is cooled well below martensitic finish temperature (up to -120 °C). Depending on part geometry the treatment is often combined with tempering treatment.

Additional services


    WSH - Surface preparation by industrial washing

    Washing of parts in special detergents aqueous solution before and/or after heat treatment. Washing before heat treatment is performed for cleaning of greasy surfaces or removal of machining or other emulsions to guarantee production stability of heat and surface treatment and highest quality of treated parts. Washing after heat treatment is mainly performed for parts quenched in oil.

    NSP - Surface preparation by shot peening

    The process of shot peening is hitting the surface with ceramic spheres to (1) clean the surface and prepare it for nitriding treatment, (2) introduce compressive stresses to the surface of the part and by that improve mechanical resistance.

    NTP - Surface preparation by thermal processes

    Correct surface preparation is fundamental for successful nitriding. Special attention must be exercised in the preparation of critical parts. NTP process is designed for the preparation of special parts before the nitriding process.

    NCP - Surface preparation by chemical/mechanical protection

    Specific surfaces in nitriding are protected, where for a certain reason hard surface is not allowed or brittleness is prevented. Examples are sharp edges, threads, surfaces for subsequent machining or others.


    HTD - HT process development based on special customer request

    Demanding technical products and most series production products can be treated to customer specification only by adopting specially developed processes. Standard heat treatment processes generally do not provide requested properties. HTD service includes the development of individual heat treatment processes for the fulfilment of specific requests. Testing of the heat treatment process in development is performed on: (1) test parts, (2) in case of highly demanding parts, on a “dummy” furnace load, and (3) on a full production furnace load. The level of testing is agreed upon with the customer before testing starts. Customer confirms results, technology is stored under customer/product ID to assure individual customer treatment.

    FIX - Development and fabrication of special fixtures for HT

    Heat treatment of demanding serial products is generally made using special fixtures that hold the products in an optimal position during treatment. Fixtures enable the products to travel fixed in optimum position throughout the process (to heating, quenching, washing, and tempering), thus assuring required mechanical, microstructural and dimensional properties of products. Service FIX includes the development and fabrication of special fixtures for holding products throughout the heat treatment process. The customer shall decide upon the development and fabrication of individual fixtures based on the technical presentation of benefits achieved.

    PPAP - Development of APQP and PPAP supporting documentation

    Production of series parts with the highest quality standards requires the preparation of documentation for exact process definition. Documentation includes exact guidance for testing, introduction and execution of production process including flow charts, risk analysis for non-conformities, and possibilities to reduce risk and errors. The production process is defined in detail, including equipment utilized, process supervision and guidance to quality assurance, packing and shipment. Our customers are offered complete preparation of APQP and PPAP procedure and execution of heat treatment process in its compliance. Processes are generally used for the production of parts for the automotive industry.

    SIM - Material and Process Modeling – virtual heat treatment

    Deformation control at heat treatment is especially critical in technically demanding series-production parts. Availability of information on residual stress state and deformation in products after heat treatment represents the basis for dimensional adjustment of products before heat treatment or adjustments of corresponding tolerance limits, so dimensionally perfect products after heat treatment are obtained. SIM technology is essentially virtualization of the heat treatment process that enables heat treatment process adjustment and control to assure product dimensions within required tolerance limits.SIM technology may also be utilized for the prediction of mechanical properties of products after heat treatment. Based on SIM results one can adjust product dimensions before heat treatment so that product after heat treatment completely satisfies both dimensional requirements as well as microstructural and mechanical properties.


    SPC - Statistical Process Evaluation and Control

    Measurements of dimensional and other key properties of products in series production are generally performed on a statistically representing sample. Based on statistical evaluation of measurement results one is capable to predict the deviation of measured parameters of the entire production. Our customers are offered a statistical evaluation of parameters measured in our laboratory to achieve high production stability and reliability.

    DIM - Dimensional Control

    Dimensional control is important when the products after heat treatment continue directly to the assembly line, or in the case when final machining is executed in automatic machines. Deformation outside tolerance limits could jeopardize the quality of final products or could provoke machine failure and stall the final machining process. Our customers are offered dimension control of their products before and/or after heat treatment. DIM could be executed on a statistical sample or on all products in series. Correction of certain dimensions (mechanical deformation process or straightening) is offered in conjunction with DIM service (see LEV service).

    DIM 3D - Dimensional Control using 3D systems

    Service is DIM executed on advanced 3D measurement equipment. The equipment can be programmed according to specific customer requests for the preparation of comprehensive measurements protocols of geometrically complex products both before and/or after heat treatment.

    LEV - Dimensional adjustment of parts after heat treatment

    LEV service is the adjustment or correction of product geometry for deformation caused by heat treatment. The dimensional tolerance range of certain products can not be met when using standard heat treatment processes. Service LEV can be of assistance in certain cases, to bring specific product dimensions after heat treatment into tolerance limits. Usually, LEV service is carried out in combination with DIM or DIM3D.


    Laboratory services

    Our customers are offered complete laboratory services, starting at individual tests and measurements down to a full mechanical and microstructural examination of materials, reporting and certification, all according to ISO 9001 and ISO TS 16949. Laboratory services we offer (for example microstructural analysis, hardness profile, chemical analysis, fracture analysis, various mechanical tests, measurement of surface-impurity contents, etc.) are specified in the laboratory service list.


    COR - Corrosion protection

    Products made of low-alloy steel are not resistant to corrosion. They shall receive corrosion protection treatment after heat treatment, especially in case of longer transportation or when kept in stock. The customer is offered technically verified corrosion protection treatments, COR service.

    PAC - Packing according to special customer request

    Customer is offered special packing service executed based on customer’s request. Service PAC is useful in case of sensitive products, high-series products, direct shipments to destinations with specific packing or product-protection requests.


    LOG - Logistic Services

    The customer is offered a complete logistic service, from pick–up at defined location and time to delivery to defined location and time.

    STOR - Storage

    The customer is offered storage of documentation pertinent to product thermal processing as well as laboratory measurements and analysis performed in our company. Documentation is stored for a defined period.

We offer various in-house rough and precise machining services.


iTherm® conformal cooled gate inserts cool quicker and bring substantial productivity improvement.


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