Twin screwsMAXI 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

NameBase AlloyAlloy ComponentsHardness (HRC)Abrasion resistanceCorrosion resistance
Stellite 1CobaltC, Cr, W52-57xxxxxx
Stellite 12CobaltC, Cr, W44-48xxxxx
Colmonoy 57NickelC, Si, Cr, B, Fe52-56xxxxxxx
Colmonoy 83NickelTungsten carbide56-60 (x)xxxxxxxxx
CastoTIG5IronCr, V58-62xxxxxx
Suitability: (x good) to (xxxxx excellent).
(x)Tungsten carbides have a hardness of 89 HRC.

Counter rotation screwScrew coatings

CoatingThickness of layer (mm)HardnessAbrasion resistanceCorrosion resistance
Chrome plating0,020 – 0,035800 – 1100 HV 0,1xxxxxxx
Nickel plating0,015 – 0,025500 – 600 HV 0,1xxxxxxx
PVD, TiN0,0042500 HV 0,5xxxxx
PVD, CrN0,0042100 HV 0,5xxxxxx
PVD, CrN-multi layer0,0082100 HV 0,5xxxxxxxx
Suitability: (x good) to (xxxxx excellent).

Base materials for plasticizing screws

DIN standardMaterialType steelTreatmentHardnessAbrasion resistanceCorrosion resistance
1.850941CrAlMo7Nitriding steelNitrided950 – 1100 HV5xx
1.855034CrAINi7Nitriding steelNitrided950 – 1100 HV5xx
1.2379X155CrVMo121Tool steelHardened59 – 63 HRCxxxxx
KPM1PM materialHardened58 – 63 HRCxxxxxxx
KPM2PM materialHardened55 – 60 HRCxxxxxxxx
Suitability: (x good) to (xxxxx excellent). PM is powder material. Other materials avaiable on request.