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.