40CrNi alloy structural steel 40CrNi round steel wholesale and retail in Shanghai

Chemical composition
Mass fraction ():
:.～
.～
Gravitational properties
[Sample blank size]
[Heat treatment]
Quenching heating temperature (℃): Coolant: oil
Tempering heating temperature (℃): Coolant: water, oil
[Mechanical properties]
Tensile strength (b/) :
Yield point:
Elongation after fracture (/):
Reduction of area (/):
Impact absorbed energy:
Brinell hardness (B/3 ) (annealed or high temperature tempered state):
Medium carbon alloy quenched and tempered steel. It has high strength, high toughness and high hardenability. In the quenched and tempered state, the comprehensive mechanical properties are good and the low-temperature impact toughness is good. It has a tendency of temper brittleness and is prone to cracks when cooled by water. The machinability is good, but the weldability is poor. Use in tempered state.
Heat treatment editor
It is a hypoeutectoid steel. It is completely austenitized after heating at ℃. When normalized and cooled, proeutectoid ferrite precipitates, and then austenite transforms into a pearlite-like structure ( lamellar). Due to the fast cooling rate and small spacing between pearlite sheets, it is easy to obtain troostite or troostite structures (both of which belong to pearlite in a broad sense). Therefore, the structure is ferrite + pearlite
Application examples
Used to manufacture forged and cold stamped important quenched and tempered parts with large cross-sections, such as connecting rods, discs, crankshafts, gears, shafts , screws, etc.
Delivery status: Edit
Delivery in a heat treatment (normalizing, annealing or high temperature tempering) or non-heat treatment state, the delivery status should be noted in the contract.
Representation method
① The two digits at the beginning of the steel number indicate the carbon content of the steel, expressed as a few ten thousandths of the average carbon content, such as alloy pipe ② The main alloying elements in the steel, except for a few micro-alloying elements In addition, it is generally expressed in percent. When the average alloy content is ., the steel number is generally marked with the element symbol instead of the content. However, in special circumstances where it is easy to cause confusion, the element symbol can also be marked with a number, such as the steel number and the chromium content of the former. is ., the latter is ., and the remaining ingredients are all the same. When the average content of alloy elements is .,.,3., the content should be indicated after the element symbol, which can be expressed as, etc. accordingly. For example.
③Alloying elements such as vanadium, titanium, aluminum, boron B, and rare earth R in steel are all micro-alloying elements. Although the content is very low, they should still be marked in the steel grade. For example, in B steel. Vanadium is..., Boron is...
④High-grade high-quality steel should be added at the end of the steel number to distinguish it from general high-quality steel.
⑤Special-purpose alloy structural steel, the steel number is preceded (or suffixed) with a symbol representing the purpose of the steel type. For example, the steel number 3 for rivet screws is expressed as 3.