R9M4K8 (EP688)
Steel has an increased tendency to decarburize, lower viscosity, increased wear resistance, reduced grindability.
For the manufacture of tools used in the processing of high-strength stainless and heat-resistant steels, alloys and improved alloyed steels under conditions of increased heating of the cutting edge (gear-cutting tools, cutters, shaped cutters, countersinks, taps). for processing high-strength stainless and heat-resistant steels and alloys under conditions of increased heating of the cutting edge: gear-cutting tools, mills, shaped cutters, countersinks, taps.
Classification
| Country | Section | Category |
|---|---|---|
| CIS, Russia, Ukraine | Tool steel | High speed tool steel |
Chemical composition
| Standard | Fe, % | Si, % | Mn, % | Co, % | Cr, % | Cu, % | Ni, % | V, % | P, % | C, % | S, % | Mo, % | W, % |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| GOST 19265-73 | 68.39–72.59 | 0.2–0.5 | 0.2–0.5 | 7.5–8.5 | 3–3.6 | < 0.25 | < 0.6 | 2.3–2.7 | < 0.03 | 1–1.1 | < 0.03 | 3.8–4.3 | 8.5–9.5 |
Information on suppliers
Physical characteristics
| Temperature, °C | $$E\cdot 10^{9}$$, $$MPa$$ | $$\varkappa$$, $$\frac{W}{m\cdot K}$$ | $$\rho$$, $$\frac{kg}{m^3}$$ |
|---|---|---|---|
| 20 | 2.29 | 8930 | |
| 100 | 25 | ||
| 200 | 27 | ||
| 300 | 28 | ||
| 400 | 29 | ||
| 500 | 30 | ||
| 600 | 31 | ||
| 700 | 32 | ||
| 900 | 32 |
Mechanical properties at 20 °C
| Rolling | Standard | Size, mm | Tension | Classifiers | $$\sigma _{U}$$, $$MPa$$ | $$\sigma_{P}$$, $$MPa$$ | $$\psi$$, % | $$KCU\cdot 10^{3}$$, $$\frac{J}{m^2}$$ | d5, % | Treatment |
|---|---|---|---|---|---|---|---|---|---|---|
| Alloy | GOST 19265-73 | annealing | 960 | 540 | 10 | 80 | 7 | delivery condition |
Brinell hardness number
| Rolling | Standard | Classifiers | Value, HBW |
|---|---|---|---|
| Alloy | GOST 19265-73 | annealing | 285 |
Critical point temperatures
| Ac1, K | Ac3(Acm), K | Ar3(Arcm), K | Ar1, K |
|---|---|---|---|
| 800 | 840 | 790 | 750 |
Analogues
| USA | Germany |
|---|---|
| T11348 | S10-4-3-10 |
Standards
| Standard | Description |
|---|---|
| GOST 19265-73 |
Description of chemical elements
| Element | Units of measurement | Description |
|---|---|---|
| Fe | % | Iron |
| Si | % | Silicon |
| Mn | % | Manganese |
| Co | % | Cobalt |
| Cr | % | Chrome |
| Cu | % | Copper |
| Ni | % | Nickel |
| V | % | Vanadium |
| P | % | Phosphorus |
| C | % | Carbon |
| S | % | Sulfur |
| Mo | % | Molybdenum |
| W | % | Tungsten |
Description of physical characteristics
| Parameter | Units of measurement | Description |
|---|---|---|
| $$E\cdot 10^{9}$$ | $$MPa$$ | Elastic modulus |
| $$\varkappa$$ | $$\frac{W}{m\cdot K}$$ | Coefficient of thermal conductivity (the heat capacity of the material) |
| $$\rho$$ | $$\frac{kg}{m^3}$$ | The density of the material |
Description of mechanical properties
| Parameter | Units of measurement | Description |
|---|---|---|
| d5 | % | Elongation at break |
| $$\sigma _{U}$$ | $$MPa$$ | Ultimate tensile strength |
| $$\sigma_{P}$$ | $$MPa$$ | Proportionality limit |
| $$\psi$$ | % | Reduction in cross section on fracture |
| $$KCU\cdot 10^{3}$$ | $$\frac{J}{m^2}$$ | Impact toughness |
Description of temperatures of critical points
| Parameter | Units of measurement | Description |
|---|---|---|
| Ac1 | K | |
| Ac3(Acm) | K | |
| Ar3(Arcm) | K | |
| Ar1 | K |