40Cr4 Lost Wax Investment Casting

Product Introduction

What kind of steel does 40Cr4 belong to?

Medium carbon modulated steel (cold heading die steel) C0.37~0.44 Si0.17~0.37 Mn0.50~0.80 Cr0.80~1.10 Ni≤0.030 P≤0.035 S≤0.035 CU≤0.030

What kind of steel is 40Cr4-B, and what is the difference between it and 40Cr?

First of all, it is not "fire", but "quenching". In the factory, in order not to be confused with "annealing", it is also called "dipping in fire".

Second: The standard pronunciation of 45 steel should be called "45 steel", not 45 steel. The carbon content of 40Cr is 0.37% ~ 0.44%, which is slightly lower than 45 steel (0.42% ~ 0.50%). The content of Si and Mn is equivalent, and the content of Cr is 0.80% ~ 1 .10%. In the case of hot-rolled supply, this 1% Cr has basically no effect, and their mechanical properties are roughly the same. Since 40Cr is about half more expensive than 45 steel, for economic reasons, those who can use 45 steel do not use 40Cr. Generally classified 45 steel belongs to GB699 "(High Quality) Carbon Structural Steel", and 40Cr belongs to GB3077 "Alloy Structural Steel". The difference lies in the heat treatment. The main role of Cr in heat treatment is to improve the hardenability of steel. Due to the increased hardenability, the strength, hardness, impact toughness and other mechanical properties of 40Cr after quenching (or quenching and tempering) are also significantly higher than that of 45 steel. However, due to the strong hardenability, the internal stress of 40Cr during quenching is also lower than that of 45 steel. 45 steel is larger. Under the same conditions, the cracking tendency of workpieces made of 40Cr material is greater than that of workpieces made of 45 steel material. Therefore, in order to avoid cracking of the workpiece, oil with low thermal conductivity is mostly used as the quenching medium when quenching 40Cr (sometimes the double-liquid quenching method is also used, commonly known as water quenching and oil cooling), while water with higher thermal conductivity is used as the quenching medium for 45 Cr. medium. Of course, the choice of water and oil is not absolute, and is also closely related to the shape of the workpiece. 40Cr parts with simple shapes can also be quenched with water, while 45 steel parts with complex shapes may have to use oil quenching or even salt bath.

What is the chemical composition and tensile strength of 40Cr and what is it suitable for?

Chemical composition of 40Cr: C0.37~0.44%\

Si0.17~0.37%\

Mn0.50~0.80%\Cr0.80~1.10% Mechanical properties: tensile strength 590~735N/mm2. Quenching and tempering treatment can obtain good comprehensive mechanical properties, low-temperature impact resistance, and good hardenability. Oil quenching can improve fatigue strength. During water quenching, parts with complex shapes are prone to cracks. Cold bending plasticity is moderate. After heat treatment, the cutting performance is good and the weldability is good. Not good. Generally used in the quenched and tempered state, it can also be carbonitrided and high-frequency quenched. It is one of the most widely used alloy structural steels. After quenching and tempering, it can be used to manufacture medium-speed and medium-load parts, such as machine tool gears, shafts, worms, spline shafts, ejector sleeves, etc.;

Quenching and tempering and surface high-frequency quenching are used to manufacture parts with high surface hardness and high wear resistance, such as gears, shafts, spindles, crankshafts, spindle sleeves, pins, connecting rods, intake valves, screws, etc. Quenching and medium temperature tempering Fire is used to manufacture heavy-load, medium-speed impact parts, such as oil pump rotors, sliders, gears, spindle sleeves, etc.; quenching and low-temperature tempering are used to manufacture heavy-load, low-impact, wear-resistant parts, such as worms and shafts. , sets, etc.;

Carbon-nitrogen treatment is used to manufacture transmission parts with larger sizes and higher low-temperature toughness, such as shafts, gears, etc.; steels that can be used instead of 40Cr include 40MnB, 45MnB, 35SiMn, 42SiMn, etc.

Detection Systems

Copper Silica Sol Investment Casting