Konturflow – GTK


For tunnel gating of small to medium-sized moldings contoured in the gate area.

Our GTK inserts are made of 1.4028 steel. This is a Catamold 420 Type hardable stainless steel which has been “through-hardened” to 50+5 HRC.    It therefore requires no subsequent case hardening or nitriding. The 1.4028 material can be WIG welded.

  • Maximum gate diameter (pointed tunnel) up to 1.7 mm.
  • Contourable up to 3 mm depth.
  • Usable for all thermoplastics including fillers up to 50% glass fibre at least.
 << Please check the instructions for the calotte design! 

  • GTK_mit_Farbe_englisch
  • >> Konturflow “Cotours up to 3 mm”Features:

    • The gate insert is placed on the molding contour directly with the original CAD reference point.
    • Calotte sized to 1.7 mm gate diameters and max. 3 mm contour depths.

  • Dimensions “GTK”

    Recommended distances “L” from the injection point to the sprue ejector are given below for the various material groups. 

    The distance “AT” describes the correlated ejector depth.


  • Thermoplastics Elastomers

    When processing thermoplastic elastomers, please observe the following recommendations to ensure reliable de-molding:

    • The distance “L” should decrease with the Shore hardness value.
    • The guide length L*0.8 does not apply to TPEs (or TPU, TPA, respectively). In these applications, a centering cone should be provided as shown in our drawing.
    • This application instruction applies to elastomers in the medium Shore hardness range (uo to 100 Shore A).


  • Gate sizes

    We would like to make it as easy as possible for you to select the right gate size. To help you make your choice we have plotted a number of charts indicating the range of possible gate sizes for a given molding weight and material. Please take into account the viscosity of the plastic before making your selection. Since the plastics industry is marketing an ever growing number of modified plastics in each category, it is impossible to provide binding data here. Please also note our warranty disclaimer.


  • EXAFLOW Tunnel Gate Inserts

    Catamold 420W-DIN 1.4028-X20Cr13  ( until July 2017,  100Cr6 1.3505 )

    Material designation:
    BASF Catamold 420W – DIN 1.4028 – X20Cr13.
    Hardable stainless steel for production of MIM-Parts.

    Components with high hardness and wear resistance combined with good corrosion resistance against water and steam; e. g. tools, cutting blades, surgical instruments, nozzles, bearings.

    • High wear resistance
    • High corrosion resistance
    • Good machinability
    • Weldable

    C = 0.35 – 0.50 %
    Cr = 12 – 14 %
    Fe = Balance

    Surface quality, roughness Ra 0.8 – 1.3

    Density 7.6 g/cm³
    Carbon content        0.35 – 0.50 %
    Hardness 50 +5 HRC
    Ultimate Tensile Strength Rm      (heat-treated)
     1560 mm²