JIS G3445 STKM18B Introduce
JIS G3445 is a standard carbon steel grade that is used in machinery and applications. It covers the dimensions, chemical composition, mechanical properties and requirements of the steel. The dimensions include the outer dimensions, wall thickness, inner dimensions, length and mass. The chemical composition includes the desired amount of carbon and the allowable levels of impurities such as sulfur and phosphorus. The mechanical properties include the strength, elongation, hardness and impact resistance of the steel.
Smelting temperature:1387°C - 1197°C
Application:Carbon steel pipe for mechanical structure
JIS G3445 STKM18B Material Chemical Composition
The chemical composition of the JIS G3445 STKM18B steel are as follows:
| Element | Min | Max |
|---|---|---|
| Silicon (Si) | - | 0.5500 |
| Sulfur (S) | - | 0.0400 |
| PhOsphorus (P) | - | 0.0400 |
| Manganese (Mn) | - | 1.5000 |
| Carbon (C) | - | 0.1800 |
JIS G3445 STKM18B Material Mechanical Properties
JIS G3445 STKM18B steel is a versatile carbon steel alloy with a variety of useful mechanical properties. It exhibits excellent yield strength, tensile strength, and elongation when heat treated properly. Its strength and durability make it a suitable option for many automotive and mechanical engineering applications.
The mechanical properties of the JIS G3445 STKM18B steel are as follows:
| YieldRp0.2 | ≤ 782 (MPa) |
| TeileRm | ≤ 269 (MPa) |
| ImpactKV/Ku | 34(J) |
| ElongationA | 32% |
| Reduction in cross section on fractureZ | 31% |
| As-Heat-Treated Condition | Solution and Aging, Annealing, Ausaging, Q+T,etc |
| Brinell hardness (HBW) | 233 |
JIS G3445 STKM18B Material Thermal Properties
The thermal performance parameters of the JIS G3445 STKM18B steel are as follows:
| Temperature (°C) | 24 | 898 | 128 |
| Modulus of elasticity (GPa) | - | 814 | - |
| Mean coefficient of thermal expaion ×10-6/(°C) | - | - | 21 |
| Thermal conductivity (W/m·°C) | - | 33.3 | 23.2 |
| Specific thermal capacity (J/kg·°C) | - | 432 | - |
| Specific electrical resistivity (Ω mm²/m) | 0.42 | - | - |
| Deity (kg/dm³) | - | - | 233 |
| Poisson’s coefficient, ν | - | - | 111 |
JIS G3445 STKM18B Material Machining Technology
A number of different machining operations can be employed when machining JIS G3445 STKM18B steel. These operations include turning, facing, drilling, reaming, and tapping. The workpiece must be securely held in the machine table before machining begins. When drilling and tapping, it is important to use the correct drill points, as incorrect drill points may cause the taps to bind or break. Additionally, when drilling deep holes, the use of a coolant is recommended as it will prevent the tool from overheating and ensure optimal performance.