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Bi-Metal

Background

In the construction and manufacturing fastening industries two things has always been very important:

  • Sustainability – how long will my fastener last in a given environment?
  • Efficiency – how quickly can I fasten it?

 

Sustainability

For decades AISI 304 and AISI 316 Austenitic Stainless Steel was considered the first, foremost and only choice in North America for outdoor use in tough environment; coastal and industrial areas, etc..

The Austenitic Stainless Steel quality which contents both Chromium and Nickel and even Molybdenum for AISI 316 has excellent corrosion performances and at the same time being very ductile with zero risk of Hydrogen Assisted Stress Corrosion Cracking (HASCC) or better known as Hydrogen Embrittlement.

Skilled US manufactures developed suitable cold forging technologies to achieve an effective manufacturing process with a high product quality with good tapping facilities for self-tapping screw, like the typically #1/4 -1-3/4” with 3/8” head with either a AISI 304 or AISI 316 stainless steel EPDM bonded washer added.

Efficiency = Self Drilling Fasteners

A game changer in the fastening industry was the invention of self-drilling screws, which shortened work processes by great lengths.

However as the AISI 300 series stainless steel screws cannot be hardened, the possibilities to make selfdrilling screws with drill points hard enough for drilling into steel was limited to fasteners made out of steel.

The Solution

AISI 300 Series based bi-metal self-drilling and self-tapping screws:

The solution to manufacture the most ideal self-drilling and self-tapping screw, is to:

  • Combining the main part of a screw made out of AISI 300 series Stainless Steel.
  • Having a drill-point and the first tapping threads in hardened Carbon Steel.

The hardened Carbon Steel part (drill point and first threads) will do the drilling and tapping which is then followed by the stainless steel part going into the application and forms the permanent fixing.

This solution brings together all the best from 2 worlds, where the main screw act and works exactly as the original US manufactured self-tapping screws – just with the extra feature where the installers saves a lot of time with self-drilling and self-tapping such screws doing all processes in one go.

Now it is possible to make construction solutions using suitable real stainless steel for all outdoor use in tough environments; coastal and industrial area, etc.

Self-drilling and self-tapping screws is of course needed in our modern world where “time is money” and where fast installation speed is expected in all cases. Now it is just possible to realize fast installation without sacrificing anything – the ideal combination of fast installation speed getting a self-drilling and self-tapping screw with the best corrosion performance in non-brittle and ductile qualities.

 

How?

The making of bimetal fasteners can be simplified into four steps

  1. Joining a piece of stainless steel and carbon steel wire
  2. Cold forging the screw with head, drill point and thread
  3. Partially hardening of the carbon steel part, meaning the drill point and the first couple of threads
  4. The finishing touch: Surface treatment

RED HORSE operates state of the art bi-metal production in our own factories with skilled, experienced and dedicated personnel. Production is highly automated, which ensures a constant and uniform quality, high output, less vulnerability and a high degree of flexibility – even in smaller quantities if
needed.

Through a continuing implementation of robot technology and production equipment designed in-house, we increase our competitiveness and flexibility all the time.

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