What is M35 steel?
M35 steel is high speed tool steel. It also is called SKH55 steel and 1.3243 steel. After the heat treatment, its hardness, red hardness and wear resistance can be improved. And the hardness can up to 67-70HRC. It is a good material for making tools which can handle high impact and abrasion. And it always is used to make advanced die, screw dies, reamer, milling cutter, iron head, punch, complex shape tools with high toughness. It is easy to do the hot and cold process. After the quenching and tempering, the hardness will be the same as M42 steel. And the hardness of them is 66±1HRC and 67±1 HRC. M35 steel properties and chemical composition as below.
1.3243 Steel Characteristics
M35 and M42 are the most popular high speed steel grades in the international. The alloy element content of M35 steel is higher, and also has the cobalt element. So its red hardness is higher. It has great hardness at high temperature. The hot hardness, machinability and wearing resistance are good.
M35 Steel Application
- It can be made all kinds of high hardness cutting tools. Such as saw blades, drills, taps, broaches, hobs and various milling cutters.
- Also, it is good material for cold forging dies, drawing dies, cutting tools and etc.
- It is widely used in the cold stamping products industry such as watch case factory and screw factory.
M35 Steel Grade Equivalent Chart
|Standard||ASTM A600||EN ISO 4957-1999||JIS G4403 : 2006||ISO 4957-1999|
|Grades||M35||HS 6-5-2-5/1.3243||SKH55||HS 6-5-2-5|
M35 Steel Chemical Composition
|EN ISO 4957-1999||0.87-0.95||≤0.40||0.03||0.03||≤0.45||3.80-4.50||1.70-2.10||5.90-6.70||4.70-5.20||4.50-5.00|
|JIS G4403 : 2006||0.87-0.95||≤0.40||≤0.030||≤0.030||≤0.45||3.80-4.50||1.70-2.10||5.90-6.70||4.70-5.20||4.50-5.00|
1.3243 Steel Physical Properties
|Density||8.14 g/cm³||0.294 lb/in³|
M35 Steel Mechanical Properties
|Hardness, Rockwell C (oil quenched from 1232°C, 5 mins)||64.8||64.8|
|Hardness, Rockwell C (oil quenched from 1177°C, 5 mins)||65.2||65.2|
|Hardness, Rockwell C (oil quenched from 1204°C, 5 mins)||65.2||65.2|
|Modulus of elasticity||207 GPa||30000ksi|
|Machinability (1% carbon steel)||45.0-50.0%||45.0-50.0%|
1.3243 Steel Forging Technology
The alloy element content of M35 steel is more than 22%. It is higher than M2 steel about 30%. It’s forging is difficult. You need to pay attention to it as the same as M42 steel forging. First of all, preheat it fully, the heat temperature is 1120℃ – 1150℃. And the temperature of the beginning is 1000℃ – 1050℃, the ending of it is must higher than 899℃. After forging, it should cold slowly and annealing on time to prevent cracking.
M35 Steel Annealing Process
If you case it up for the annealing after the forging, you will get a better result. If you can not do that, just make it cold to the indoor temperature then make it in. About the annealing process, just put it in the stove with the temperature which is lower than 500℃. Then heat to 840-860℃, keep the temperature for four to five hours. Furnace cooling to 500℃ below than out of it. Cooling slowly in the annealing furnace. After the annealing, its hardness is lower than 255HB.
In order to prevent oxidative decarburization happen, the annealing should be careful. And there is an easy way can do that. Just put some wood dust to the annealing furnace.
M35 Steel Quenching and Tempering Technology
|Heat Temperature in Quenching( ℃ )||Quenching Grain Fineness Number( Level )||Hardness for after Quenching( HRC )||Hardness for after Tempering( HRC )|
Notice for Quenching and Tempering
- Preheat two times: 600℃, 860℃. And the time of preheating is twice the time of heating.
- The request of quenching is 10-12s/mm.
- Needs the step hardening: 600℃→260-280℃→air cooling.
- The temperature of secondary hardening is 535-540℃ around. The hardness is bigger than 68HRC for after tempering. But the factories do not want the hardness of cutting tool is more than 68HRC due to the request for production. So it always is been tempering.
As we can see from the table, the best temperature for quenching is in the range of 1215-1225℃. In this condition, it is suitable for annual cutting tools. Its hardness is about 67-67.5HRC. It satisfies the needs of high speed steel for high strength, high hardness and high wear resistance.
M35 steel that been quenching at the temperature below 1190℃ is good material for cold work die and low-speed cutting tools. And if it been quenching at the temperature higher than 1230℃ which will have a great red hardness. It will be a good choice for turning tools and etc. Quenching it in that way will cause overheating. But it is not a trouble, the key is to control it in the right way. Some cutting tools are overheating to be more useful.
1.3243 Steel Quality Certificate
We have our own cutting and processing equipment. Specifications can be cut and customized according to your requirements.
We are a professional special steel stockist and supplier with a high-quality stand for many years. As a professional M35 steel supplier, please contacts us for any request of it. Songshun Steel always with you.