Introduction Of Nitriding Technology For Extruder Die Head?
Introduction of Nitriding Technology for extruder die head?
We know that nitriding and heat treatment are two ways of extruder die head? extrusion. Nitriding technology is more pure, because it has a long history. Nitriding is also known as diffusion nitriding. As the products treated by this method have excellent wear resistance, fatigue resistance, corrosion resistance and high temperature, its application gradually expanded. Such as extruder die head?, drill bit, screwdriver, extruder die head?, die-casting mold, and press and modeling, connecting rod, crankshaft, suction and exhaust valves and gear cams are used.
Introduction to Nitriding Steel
The traditional extruded die aluminum, chromium, vanadium and molybdenum elements of nitriding is very helpful. These elements in the nitriding temperature, and the initial nitrogen atoms in contact, it generates a stable nitride. In particular, the molybdenum element is not only used as a nitride element, but also as a decrease in the brittleness occurring at the nitriding temperature. Other elements in the alloy steel, such as nickel, copper, silicon, manganese, nitriding characteristics of no much help. In general, if the steel contains one or more nitride-forming elements, the effect of nitriding is relatively good. Aluminum is the strongest nitride element, containing 0.85 ~ 1.5% aluminum nitriding results the best. In chromium chrome steel, if there is sufficient content, can also get very good results. But there is no alloy of carbon steel, because of its formation of nitriding layer is very brittle, easy to peel off, not suitable as nitriding steel.
General extruder die head? commonly used nitriding steel has six as follows:
(1) low-alloy steel containing aluminum (standard nitriding steel)
(2) Medium carbon low alloy steel containing chromium element SAE4100,4300,5100,6100,8600,8700,9800.
(3) Hot work die steel (containing about 5% chromium) SAEH11 (SKD-61) H12, H13
(4) fat iron and Ma Tian scattered iron stainless steel SAE400 system
(5) Osti Iron Stainless Steel SAE300 Series
(6) precipitation hardening type stainless steel 17-4PH, 17-7PH, A-286 and so on
Aluminum extruder die head? Standard Nitriding Steel has a high hardness and a high wear-resistant surface after nitriding, but its hardened layer is also very brittle. On the contrary, chromium-containing low-alloy steel hardness is low, but the hardening layer that is more toughness, the surface also has considerable wear resistance and bunch of heart. Therefore, the choice of materials, should pay attention to the characteristics of materials, make full use of its advantages, to meet the function of parts. As for the tool steel such as H11 (SKD61) D2 (SKD-11), that is, high surface hardness and high heart strength.
Nitriding Technology of extruder die head?
After quenching the parts, in the nitriding treatment before the end of the need to clean the bottom, will include cleaning the nitriding process is described as follows:
(1) Extrusion of the mold head before nitriding the surface cleaning
Most of the parts, you can use the gas to the oil immediately after the oil nitriding. However, if the final processing method before nitriding is polished, polished, polished, etc., it may produce a surface layer that hinders nitriding, resulting in uneven nitriding or bending defects such as nitriding. In this case, one of the following two methods should be used to remove the surface layer. The first method is to remove the gas first before nitriding. Then use the alumina powder to make the surface abrassive cleaning. The second method is to surface the phosphate coating treatment (phosphate coating).