Very popular High Speed Steel with very good wear resistance associated with a good toughness and an excellent resistance to softening at high temperature
3348 PRIME;
- is a high speed steel produced by a process that allows it to obtain very high cleanliness and very fine structure, which improves its toughness.
- has very good wear resistance.
- has excellent resistance to softening at high temperature.
- has good toughness.
- shows good suitability for surface treatments such as gas, ionic or salt bath nitriding, as well as PVD or CVD coatings.
Applications
3348 PRIME can be used for fine cutting tools (punches and dies) and cold working tools as cold flow pressing tools.
3348 PRIME can also be used for cutting tools as drills, milling cutters, broaches, taps, dies, spindles, reamers, thread rolling combs, segments for circular saws, etc and also, reamers, shear blades, cold working cylinders, rolling cylinders for threading.
Main properties
- Good toughness
- Very good grindability
- High hardness and excellent resistance to softening at high temperature
- High compressive strength
- High hardenability
Chemical composition (typical)
| C | Mn | Si | P | S | Cr | Mo | V | W |
|---|---|---|---|---|---|---|---|---|
| 1.00 | ≤ 0.40 | ≤ 0.70 | ≤ 0.030 | ≤ 0.030 | 4.00 | 8.70 | 1.95 | 1.80 |
Designation
| Werkstoff Nr | ISO | China GB | JIS Japan | UK | AISI USA | Russia Gost | AFNOR | Other / Special |
|---|---|---|---|---|---|---|---|---|
| 1.3348 | HS2-9-2/ X100MoCrVW9 4 2 2 | – | SKH58 | BM7 | M 7 | – | – | – |
Structure
The structure of the 3348 PRIME is fine and homogeneous without precipitation or alignments of big carbides. The carbide distribution and the micro cleanliness are controlled and in conformity with the Stahl-Eisen Werkstoff Blatt 1570 / 61 standard.
Hardness at the time of delivery
Annealed for 280 HB max
Physical properties
| Temperature | 20°C | 350°C | 700°C |
|---|---|---|---|
| Volumic mass kg/m³ | 8300 | 8130 | 7950 |
| Young Modulus N/mm² | 217000 | 198000 | 175000 |
| Thermal conductivity W/m.K | 19.5 | 18.1 | 18.1 |
| Coefficient of linear expansion 10-6/K | 11.7 | 12.9 | 13.2 |
Heat treatment
Soft annealing
Temperature: 820 – 870°C, duration 1h + 1h for 25 mm thickness. slow cooling in the oven (10 to 20°C/h). The atmosphere in the furnace must be reducing to avoid decarburization of the steel.
Stress relieving
After machining, it is recommended to perform stress relieving at 600 – 650°C for a minimum of 2 hours, followed by slow cooling in the oven to 450°C.
Austenitization
In order to avoid any risk of cracking it is recommended to preheat in 3 steps.
- 1st preheating step: temperature: 500°C time: 30 s/mm of thickness
- 2nd preheating step: temperature: 850°C time: 30 s/mm of thickness
- 3rd preheating step: temperature: 1050°C time: 30 s/mm of thickness
Recommended austenitizing temperature: 1180 – 1220°C. The holding time should not be too long to avoid a risk of grain coarsening and a loss of toughness. It is recommended to keep the part at the austenitizing temperature 30 minutes per inch of thickness as soon as the temperature of the surface reach the austenitization temperature.
Sub zero treatment
For parts that need to have high dimensional stability and to increase wear resistance without reducing toughness, it is recommended to perform a subzero treatment at a temperature between -70°C and -190°C for 1 hour for 25 mm of thickness of the part. The temperature range from -70°C up to -120°C (named cold treatment of steel) leads to the complete transformation of austenite into martensite and as a consequence to better stability associated with improved hardness and better wear resistance. On the 3348 PRIME such a treatment leads to an increase of 100% of the wear resistance (wear ratio).
The temperature range from -135°C down to -190°C (named cryotreatment of steel) leads also to the complete transformation of austenite and also the precipitation of ultra fine carbides improving a lot the wear resistance without modification of the toughness and on 3348 PRIME such a treatment leads to an increase of 200% of the wear resistance (wear ratio).
This treatment is optional for common applications.
Quenching medium
Oil at 80°C, vacuum (pressure> 6 bars), salt bath 500 – 550°C.
To ensure good toughness, treatment with oil or salt bath is preferable.
After quenching the hardness is 64 – 66 HRC.
Tempering
To ensure a minimum residual austenite rate as well as greater tool stability, it is essential to perform a double (triple is better) tempering. Each tempering is followed by a cooling under 100°C.
The recommended tempering temperature is 540 to 560°C. The hardness after tempering is 64 HRC and suitable for all the applications of the 3348 PRIME. Each tempering time must be at least equal to 1h + 1h for 25 mm of thickness of the treated part (equivalent thermal thickness).
Surface treatment
PVD, CVD
3348 PRIME is suitable for all kinds of PVD and CVD treatment as soon as the treatment temperature is 30°C lower than the last tempering temperature.
Polishing
3348 PRIME could be polished the treated state and can be used for applications requiring a sufficiently polish level for translucent parts.
Optimal polishing is achieved by performing consecutive steps of fairly close roughness and stopping each step as soon as the last scratch of the previous step disappears.
Machining
The machining parameters below are given for information only and must be adapted according to the equipment and usual machining conditions.
Grinding in annealed conditions
| Carbide tool | Solid tool | ||
|---|---|---|---|
| Rough machining | ½ Finishing | Finishing | |
| Cutting speed m/min | 110 – 130 | 125 – 160 | 40 – 50 |
| Feed mm/r | 0.35 | 0.15 | 0.01 – 0.1 |
| Depth of cut mm | 2 – 3 | 1 – 1.5 | 0.01 – 0.1 |
Turning in annealed conditions
| Carbide tool | HSS tool | ||
|---|---|---|---|
| Rough turning | Finishing | Turning | |
| Cutting speed m/min | 110 – 140 | 165 – 200 | 15 |
| Feed mm/r | 0.35 | 0.15 | 0.1- 0.2 |
| Depth of cut mm | 2 – 3 | 1 – 1.5 | 0.5 – 2.0 |
Drilling in annealed conditions: HSS twist drill
| Drill diameter mm | Cutting speed m/min | Feed mm/r |
|---|---|---|
| <5 | 11 | 0.07 |
| 5-10 | 0.15 | |
| 10-15 | 0.22 | |
| 15-20 | 0.30 |
Drilling in annealed conditions: carbide drill
| Insert | Solid | |
|---|---|---|
| Cutting speed m/min | 130 | 70 |
| Feed mm/r | 0.10 | 0.20 |
Fine grinding
General indications for grinding wheels to be used on 3348 PRIME in the heat treated condition
Usually, rather soft vitrified aluminum oxide grinding wheels (grades G for plane grinding to K for cylindrical grinding) are used.
Particular attention will be paid to effective cooling of the surface during grinding to prevent degradation of the material surface.
Electro-discharge machining
3348 PRIME is also suitable for EDM machining (wire or electrode). Preferably, the machining will be carried out with a low current density and a high frequency in order to limit the thickness of the white layer as much as possible.
Then it is necessary to carry out a stress relieving at 25°C below the last tempering in order to reduce the level of residual stresses (which could lead to a risk of cracking) and to carry out a polishing to completely remove the white layer formed during the discharge machining process.
Welding
3348 PRIME cannot be welded.
Download the 3348 PRIME datasheet (PDF)
More grades: High Speed Steels. Where to buy: Service Network.
