1 Tap design and manufacture in the steel pipe fitting
a. Choose a better tap material. Adding special alloy elements to ordinary high-speed tool steel can significantly improve the wear resistance and toughness of the tap.
b. Coating titanium nitride coating into the surface of the tap thread can significantly improve the wear resistance, heat resistance, and lubricity of the tap.
C. Properly increase the front corner of the faucet. However, it should be noted that if the rake angle of the tap is too large, it is easy to cause the tap to collapse when the tool is retracted, and the tapped thread will become multi-edged.
d. Appropriately increase the number of tap water shovel back. However, it should be noted that if the amount of shoveling back is too large, it is easy about the chips to be stuffed into the rear corner of the tap when the tool is retracted, and the finish of the tapping is not good.
e. Reasonable choice of tool heats treatment method to consider the hardness and toughness of the tap.
2 Workpiece bottom hole in the steel pipe fitting
According to the principle of tapping, the bottom L size of the workpiece should be minimized, especially the American standard NPT thread and the British standard f, r thread, the taper is 1:16, and most stainless steel manufacturers follow this thread. The small diameter end casts a straight hole into the bottom hole of the tapping, which will cause a lot of processing in the second half of the tapping, which may cause the following undesirable consequences:
①The tap torque is large, the tap is easy to break or chip;
②Poor finish of tapping;
③When testing with a plug gauge, the diameter of the tapped cylindrical thread is too small. The reason is not that the thread pitch is inconsistent, but the thread is scraped by chips and has burrs.
3 Reasonable use of taps in the steel pipe fitting
When processing different types of workpieces, different chip trends should be considered. When necessary, grinding is required. The principle of grinding is to discharge as many chips as possible from the chip cavity during tapping to prevent scratches on the machined threads.
Post time: Oct-31-2023