ESRed stainless mold steel for either good corrosion resistance and very high wear resistance
TGP 16 is stainless steel, which can be used for making small and medium-sized plastic injection molds where a good corrosion resistance associated with a high wear resistance is required.
Applications
TGP 16 has both very high wear resistance, excellent corrosion resistance, excellent polishability (suitable for transparent parts) as well as correct machinability.
If higher polish ability is required (eg. for miror polish) we recommend to use the CROMIS ESR (remelted steel with the highest cleanliness).
TGP 16 can be used for injection moulds for corrosive plastic (PVC, recycled plastics), and also especially for moulds designed for plastics reinforced with abrasive fillers, extrusion screws and barrels for extruders, moulds for food, medical and optical equipment.
TGP 16 is delivered in the annealed condition and in use it should be treated to a hardness of 52 HRC.
Main properties
- Good corrosion resistance
- Very good wear resistance
- Very Good polishability
- High hardenabilty
Chemical composition (typical)
| C | Mn | Si | P | S | Cr | Mo | V |
|---|---|---|---|---|---|---|---|
| 0.40 | 0.55 | 1.05 | < 0.015 | <0.005 | 13.5 | 0.22 | 0.30 |
Designation
| Werkstoff Nr | ISO | China GB | JIS Japan | UK | AISI USA | Russia Gost | AFNOR | Other / Special |
|---|---|---|---|---|---|---|---|---|
| 1.2083 mod | X40Cr13 | – | – | – | 420 mod | – | – | – |
Structure
The structure of the TGP 16 is fine and homogeneous without precipitation or alignments of carbides.
Hardness at the time of delivery
Annealed for 220 HB max.
Typical mechanical properties in hardened conditions (results from internal tests not indicated on the certificates)
| TS MPa | YS 0.2% MPa | Hardness HRC | KU J à 20°C |
|---|---|---|---|
| 2050 | 1450 | ≥ 56 | ≥ 15 |
Physical properties
| Temperature | 20°C | 200°C | 400°C |
|---|---|---|---|
| Volumic mass kg/m³ | 7800 | 7750 | 7700 |
| Young Modulus N/mm² | 239000 | 211000 | 181000 |
| Thermal conductivity W/m.K | 21.2 | 23 | 24.2 |
| Coefficient of linear expansion 10-6/K | 11.2 | 11.2 | 11.5 |
Heat treatment
Soft annealing
Temperature: 860°C, duration 1h + 1h for 25mm thickness. slow cooling in the oven (10 to 20°C/h). The atmosphere in the furnace must be reducing to avoid decarburization of the steel.
Stress relieving
After machining, it is recommended to perform stress relieving at 650°C for a minimum of 2 hours, followed by slow cooling in the oven to 450°C.
Austenitization
In order to avoid any risk of cracking it is recommended to preheat in 2 steps and eventually 3 steps for bigger parts:
- 1st preheating step: temperature: 600°C time: 30 s/mm of thickness
- 2nd preheating step: temperature: 850°C time: 30 s/mm of thickness
Recommended austenitizing temperature: 1000 – 1050°C. The holding time should not be too long to avoid a risk of grain coarsening and a loss of toughness. It is recommended to keep the part at the austenitizing temperature 30 minutes per inch of thickness as soon as the temperature of the surface reach the austenitization temperature.
Sub zero treatment
For parts that need to have high dimensional stability and to increase wear resistance without reducing toughness, it is recommended to perform a subzero treatment at a temperature between -70°C and -190°C for 1 hour for 25 mm of thickness of the part.
The temperature range from -70°C up to -120°C (named cold treatment of steel) leads to the complete transformation of austenite into martensite and as a consequence to a better stability associated with an improved hardness and a better wear resistance and the temperature range from -135°C down to -190°C (named cryotreatment of steel) leads also to the complete transformation of austenite and also the precipitation of ultra fine carbides improving a lot the wear resistance without modification of the toughness. This treatment is optional for common applications.
Quenching medium
Oil at 80°C, vacuum (pressure > 6 bars), salt bath 500 – 550°C.
To ensure good toughness, treatment with oil or salt bath is preferable.
Tempering
To ensure a minimum residual austenite rate as well as greater tool stability, it is essential to perform a double tempering. Each tempering is followed by a cooling under 100°C.
Each tempering time must be at least equal to 1h + 1h for 25 mm of thickness of the treated part (equivalent thermal thickness).
Tempering temperature and corrosion resistance: In order to avoid a better corrosion resistance it is highly recommended to avoid tempering temperatures in the range 400 to 550°C since at these temperatures there is a precipitation of chromium carbides at the grain boundaries leading to an increase of the local corrosion at these locations.
For the higher hardness (better wear resistance) tempering temperatures lower than 400°C are recommended and for lower hardness (better toughness) tempering temperatures over 550°C are recommended.
Surface treatment
Nitriding
TGP 16 can be nitrided at temperatures less than or equal to 20°C below tempering temperatures without risk of deterioration of the mechanical characteristics.
Nitriding at a temperature over 550°C is recommended to avoid any risk of carbide precipitation at the grain boundaries.
PVD, CVD
TGP 16 is suitable for all kind of PVD and CVD treatment as soon as the treatment temperature is 30°C lower than the last tempering temperature.
Polishing
TGP 16 is suitable for polishing in the heat treated condition and it can be used for applications requiring a high polished level (Rt ≤ 0.2 µm, CNOMO level 1, Rugotest N4) as used for transparent parts.
Optimal polishing is achieved by performing consecutive steps with similar roughness and stopping each step as soon as the last scratch from the previous step disappears.
Texturing
TGP 16 is suitable for chemical or laser texturing.
Machining
The machining parameters below are given for information only and must be adapted according to the equipment and usual machining conditions.
Turning
| Carbide tool Rough machining |
Carbide tool Finishing |
HSS tool Finishing |
|
|---|---|---|---|
| Cutting speed m/min | 160 – 200 | 210 – 250 | 17 – 22 |
| Feed mm/r | 0.2 – 0.4 | 0.1 – 0.2 | 0.1 – 0.3 |
| Depth of cut mm | 2 – 4 | 0.5 – 2 | 0.5 – 2 |
Milling: surfacing
| Milling with carbide tools Rough machining |
Milling with carbide tools Finishing |
|
|---|---|---|
| Cutting speed m/min | 160 – 200 | 250 – 280 |
| Feed mm/r | 0.2 – 0.4 | 0.1 – 0.2 |
| Depth of cut mm | 2 – 4 | 0.5 – 2 |
End milling
| Milling with carbide tools Solid carbide |
Milling with carbide tools Carbide indexable insert |
HSS milling tool Finishing |
|
|---|---|---|---|
| Cutting speed m/min | 120 – 150 | 160 – 210 | 25 – 29 |
| Feed mm/r | 0.02 – 0.2 | 0.07 – 0.2 | 0.01 – 0.3 |
Drilling: HSS twist drill
| Drill diameter mm | Cutting speed m/min | Feed mm/t |
|---|---|---|
| < 5 | 14 – 16 | 0.05 – 0.15 |
| 5 – 10 | 14 – 16 | 0.15 – 0.20 |
| 10 – 15 | 14 – 16 | 0.20 – 0.25 |
| 15 – 20 | 14 – 16 | 0.25 – 0.30 |
Drilling: carbide drill
| Carbide type | Indexable insert | Solid carbid | Carbide tip |
|---|---|---|---|
| Cutting speed m/min | 180 – 210 | 80 – 100 | 70 – 80 |
| Feed mm/t | 0.05 – 0.10 | 0.10 – 0.25 | 0.15 – 0.25 |
Fine grinding
General indications for grinding wheels to be used on TGP 16 in the heat treated condition.
Usually, rather soft vitrified aluminum oxide grinding wheels (grades G for plane grinding to K for cylindrical grinding) are used.
Particular attention will be paid to effective cooling of the surface during grinding to prevent degradation of the material surface.
Electro-discharge machining
TGP 16 is also suitable for EDM machining (wire or electrode). Preferably, the machining will be carried out with a low current density and a high frequency in order to limit the thickness of the white layer as much as possible. Then it is necessary to carry out a stress relieving at 25°C below the last tempering in order to reduce the level of residual stresses (which could lead to a risk of cracking) and to carry out a polishing to completely remove the white layer formed during the discharge machining process.
Welding
It is not recommended to weld TGP 16 but if this is mandatory it could be welded either in the annealed condition (better) or in the heat treated condition.
- Method: TIG
- Feeder wire: AISI 420
- Preheating: 250°C. hold at 200°C during the welding operation.
- Post treatment:
- In the treated state: tempering for a minimum of 2 hours at 20°C below the initial tempering temperature
- In the annealed state: carry out a soft annealing under the usual conditions: temperature: 840 – 870°C, duration 1h + 1h for 25 mm of thickness. slow cooling in the oven (10 to 20°C/h).
Download the TGP 16 DENTEX ESR datasheet (PDF)
More grades: Plastic Mold Steels. Where to buy: Service Network.
