PLASTIC MOULD STEELS
Plastic mould steels produced by Lucchini RS are designed to obtain optimum performance to meet the most complex requirements. These materials are named KeyLos® or EskyLos® depending on the production process.
Desired Material Properties:
- High wear resistance
- Excellent toughness
- Superior polishability
- Photo texturing suitability
- Corrosion resistance
- Good machinability
Quality List & Catalogs
- General Properties
- Comparison Table
- Production Process
- Heat Treatment
- Physical & Mechanical
- Documents
PLASTIC MOULD STEELS
Plastic mould steels produced by Lucchini RS are designed to obtain optimum performance to meet the most complex requirements. These designed materials are named KeyLos® or EskyLos® depending on the production process.
The KeyLos® family is produced with VD (Vacuum Degassing) technology. On the other hand, the product family called EskyLos® is produced with VD + ESR (Vacuum Degassing + Electro Slag Remelting).
These techniques bring material quality requirements as well as the most difficult quality requirements to high standards in terms of micro-cleanliness.
The main properties of the steel grades belonging to the KeyLos® family are as follows;
- Wear resistance
- Corrosion resistance against aggressive materials
- Toughness
- Polishability
- Photo texturing suitability
- Weldability
- Hardenability
- Machinability
The properties listed above affect mould behaviors during use.
These steels can be divided into 3 groups: Pre-hardened steels, Soft-annealed steels, and Aged steels.
Pre-hardened steels:
As the name suggests, steels in this family are delivered in hardened and tempered condition. These materials can be used directly in production without the need for hardening.
The advantages of using pre-hardened materials can be listed as follows: Shortening of mould manufacturing time and preventing deformations, distortions and breakages after heat treatment.
Soft annealed steels:
Some members of the KeyLos® family are delivered soft annealed to have a hardness of at most 250 HB. Unlike pre-hardened steels, since they do not have hardness, they can be used after heat treatment in the manufacturing stage.
The advantages of using soft-annealed material can be listed as follows: Homogeneous distribution of mechanical properties throughout the material, short machining time, and high wear resistance.
Aged steels:
Aged steels are based on different technological and theoretical principles than traditional materials. These materials have a hardness similar to pre-hardened materials. In order to obtain the desired mechanical properties, heat treatments are performed at 550°C – 600°C for alloy steels and at 480°C – 600°C for stainless steels.
The hardening process occurs without passing through phase transformation temperatures. In this respect, their dimensional accuracies are higher compared to traditional materials.
Plastic Mould Steels Comparison Table
These steels, which have their own unique application types and required chemical and physical properties, are produced using highly specialized and modern manufacturing methods. All grades in the BeyLos® family are produced with a special technique known as "Super Clean". In this special production process, an extremely small amount of inclusions remains in the structure. While it is well known that this parameter is one of the important parameters in the micro-cleanliness of steel, it is also an important and necessary parameter for demanding plastic mould applications, similar to the demanding applications used for hot work steels.
Furthermore, thanks to Vacuum Degassing (VD), keeping gases such as hydrogen, nitrogen, and oxygen at low levels is possible with this method. These gases cause inclusions and blowholes, adversely affecting the performance of the materials.
Using the ESR method in steel production provides the following advantages:
- Increase in the toughness of the material
- High level of micro-cleanliness
- The material being isotropic in all directions
- Very low amount of segregation
The ESR method is based on the ingot melting process. Throughout the traditional Vacuum Degassing (VD) process, a copper ingot mould containing slag is used. The ingot melts, the liquid metal passes through the slag, and the slag acts as a filter and protects the liquid steel from inclusions. The solidification process is faster in the solidification method within the mould compared to traditional methods. As a result, a homogeneous and isotropic material is obtained.
KeyLos® grades can be delivered soft-annealed and normalized, as well as pre-hardened upon request. If different hardness values are to be achieved by heat treatment, it is recommended to comply with the parameters given in the tables. The values given are only a reference and vary according to thickness and temperature steps.
These are average hardness values obtained by oil tempering. The second heat treatment is performed at a temperature 30 – 50°C lower and serves as a stress relief cycle. Austenitizing temperatures and heating methods are specified in the table.
The thermal conductivity coefficient represents the heat transfer capability of the material. If we compare two moulds with the same type and shape, the mould with a high thermal conductivity coefficient will have better and more heat dissipation in the same period of time compared to the one with low thermal conductivity. It is a very important parameter to be considered in material quality selection and positively affects mould efficiency.
INDUCTION HARDENING
It is possible to harden the KeyLos® family with induction. Tempering is recommended after cooling to room temperature.
NITRIDING
Gas and plasma nitriding are suitable for KeyLos® family. This application is suitable for moulds exposed to stress. As a result of the application, the lifetime of surface-hardened moulds or parts increases. In modern nitriding processes, the dimensions of the parts are preserved and no change occurs after the process. In this respect, it is recommended to apply it to moulds or parts whose machining is finished.
KAYNAK
If you act in accordance with the recommended procedures, good results are obtained.
ELECTRICAL DISCHARGE MACHINING (EDM)
Although obtaining complex-shaped surfaces is possible with the EDM method, the KeyLos® family can easily be machined with this method. A stress relief heat treatment is recommended after the EDM process.
FOTO DESENLEME
KeyLos® family is suitable for Photo Texturing.
PARLATMA
Plastic steels belonging to KeyLos® family are highly suitable for polishing. To obtain mirror finish, it is recommended to use EskyLos® products produced by ESR (Electroslag Remelting) method.