MAXI MELT can supply a complete range of twin screws, cylindrical and conical. Based on our large experience we can recommend the proper type of steel and surface treatment to minimize wear. According to customer’s needs we can propose nitriding steel with welding and plasma on flights top.
We deliver screws according to OEM’s design that match the original geometry. But we can also deliver screws with a proprietary design developed by our engineers. The development of proprietary design is based on deep polymer background and wide experience in polymer processing, which may also help you in the optimisation of your production. Up to date machinery and CAD CAM facilities make possible to manufacture also screws with complex design over a large scale of products with tight tolerances and very fine surface finish.
Welding on screw flights
| Name | Base Alloy | Alloy Components | Hardness (HRC) | Abrasion resistance | Corrosion resistance |
|---|
| Stellite 1 | Cobalt | C, Cr, W | 52-57 | xxx | xxx |
| Stellite 12 | Cobalt | C, Cr, W | 44-48 | xx | xxx |
| Colmonoy 57 | Nickel | C, Si, Cr, B, Fe | 52-56 | xxx | xxxx |
| Colmonoy 83 | Nickel | Tungsten carbide | 56-60 (x) | xxxxx | xxxx |
| CastoTIG5 | Iron | Cr, V | 58-62 | xxxx | xx |
Suitability: (x good) to (xxxxx excellent).
(x)Tungsten carbides have a hardness of 89 HRC.
Screw coatings
| Coating | Thickness of layer (mm) | Hardness | Abrasion resistance | Corrosion resistance |
|---|
| Chrome plating | 0,020 – 0,035 | 800 – 1100 HV 0,1 | xxxx | xxx |
| Nickel plating | 0,015 – 0,025 | 500 – 600 HV 0,1 | xx | xxxxx |
| PVD, TiN | 0,004 | 2500 HV 0,5 | xxx | xx |
| PVD, CrN | 0,004 | 2100 HV 0,5 | xxx | xxx |
| PVD, CrN-multi layer | 0,008 | 2100 HV 0,5 | xxxx | xxxx |
Suitability: (x good) to (xxxxx excellent).
Base materials for plasticizing screws
| DIN standard | Material | Type steel | Treatment | Hardness | Abrasion resistance | Corrosion resistance |
|---|
| 1.8509 | 41CrAlMo7 | Nitriding steel | Nitrided | 950 – 1100 HV5 | x | x |
| 1.8550 | 34CrAINi7 | Nitriding steel | Nitrided | 950 – 1100 HV5 | x | x |
| 1.2379 | X155CrVMo121 | Tool steel | Hardened | 59 – 63 HRC | xxx | xx |
| – | KPM1 | PM material | Hardened | 58 – 63 HRC | xxxx | xxx |
| – | KPM2 | PM material | Hardened | 55 – 60 HRC | xxx | xxxxx |
Suitability: (x good) to (xxxxx excellent). PM is powder material. Other materials avaiable on request.
