The first key knowledge point in thread machining is understanding the matching relationship between "taper material" and "workpiece material". Common thread tool material characteristics include hardness, bending strength, and breaking toughness; thread workpiece material characteristics include physical properties (softness, hardness, brittleness, toughness, ductility, and adhesion); chip characteristics (powder, flakes, filaments, long strips, and long coiled chips), etc. These are all key factors in determining the selection of thread tools to facilitate chip removal, and in selecting thread tool materials (including cobalt high-speed steel and tungsten steel) to improve torque resistance, toughness, and wear resistance to optimize tool life and meet the needs of automated mass production.
Threading tools are not independent products. There is a direct relationship between the tool material, tool hardness, toughness, wear resistance and the workpiece material's hardness, toughness, ductility, work hardening tendency and adhesion properties.
Therefore, the first-level relationship can be selected based on the following criteria:
The material of the workpiece is mainly determined by the requirements of the customer's end-use industry.
→ Material properties are determined by: physical properties (softness × hardness × brittleness × toughness × ductility × adhesion).
→ Different cutting behaviors are produced: chip characteristics (powder chips × flake chips × filamentous chips × long chips × long convoluted chips × sticky chips)
→ Factors influencing tap material selection include: high torque, high wear resistance, high temperature resistance, resistance to high-temperature annealing, and anti-adhesion properties.
→ Further factors affecting tap structure and cutting method include: chip removal type, forced cooling and lubrication, and optimized chip removal path.
So :
The material of the tap is not chosen independently, but is determined by the combination of "thread specification × workpiece material × working conditions".
Therefore, how to choose a tap ?
"Is it M6 × 1.0 – 6H, or M8 × 1.25 – 6H?"
First, you should confirm :
What material is being machined for "M6 × 1.0 – 6H / M8 × 1.25 – 6H"? Is the thread through/non-through? What is the thread depth?