AEB-L and Sandvik 13C26

Heat treating AEB-L or 13C26 Stainless steels

 

Chemical composition 13C26 (nominal) %
C	Si	Mn	P	S	Cr
0.68	0.4	0.7	≤0.020	≤0.010	13.0
Chemical composition AEB-L (nominal) %
C	Si	Mn	P	S	Cr
0.67	0.4	0.6	≤0.020	≤0.010	13.0

How the hardening parameters affect the product properties

• Too high hardening temperature gives low hardness and bad wear resistance due to excessive content of retained austenite.
• A low hardening temperature gives low hardness and reduced corrosion resistance.
• Too long holding time at the optimal hardening temperature increases the amount of retained austenite and lowers the hardness.
• Too short holding time at the optimal hardening temperature has the same effect as low austenitizing temperature.
• The maximum hardness will be obtained at a retained austenite content of about 15%.
• Deep freezing, i.e. cooling to below room temperature, increases the hardness by about 1–2 HRC.
• With deep freezing, the highest possible hardness will be achieved by increasing the hardening temperature.
• High cooling rate after hardening is necessary to avoid brittleness and reduced corrosion resistance. 600°C (1112°F) should be reached within 1–2 minutes and room temperature within 30 minutes.
• Second attempts at hardening are generally not recommended as it will not give optimal product properties.

Austenizing Temperature

Based on the charts at the end of this page an austenizing temperature of 1940°F will be used with a soak time of 15 minutes for the maximum hardness possible.

 

Preheat: Heat to 1,560° and equalize, place knives in furnace once this temperature has been reached.

1,940°F Austenitize: Ramp to 1,940°F and hold at temperature for 15 minutes.

Austenizing times based on material thickness for 13C26

Thickness, mm	Thickness, in.	Time, minutes
2.5	0.100	5
3.0	0.118	6
3.25	0.128	7
3.5	0.138	8
3.75	0.148	10
4.0	0.157	12
4.9	0.192	25

 Quenching

Quench as rapidly as possible. For optimal results 600°C (1110°F) should be reached within 2 minutes or less.

Quenching medium can be performed by plate and forced air or oil.

Until room temperature is reached the blade will remain flexible and correcting warps is possible.

Deep freezing

Cryogenic temperature is -70C or -95F The material only needs to reach the desired deep freezing temperature, no soaking-time is required. For this temperature you can use dry ice as this can attain -112F. NG CHART

Tempering Chart

Assorted charts for heat treating

 

NOTES:

1. Warpage: By adding talcum powder to your foil packets you can reduce the risk of the blade sticking to the foil pack and reduce one risk of warping.
2. I also bolt the blades between angle iron before placing into dry ice which prevents warping.
3. Use of Condursal Z1100 eliminates one possible cause of warpage caused by tool wrap sticking.
4. This is everything I have gathered to date on heat treating AEB-L and 13C26 feel free to use all or parts of the heat treating schedule.
5. If you find the blades are still to soft to handle right after the quench you can either leave between the quench plates until they reach room temperature or remove and clamp to a flat surface. I use either a second set of steel plates or stack and clamp between flat bar.

Evenheat Furnace Schedule

Step #3 allows me to remove and quench up to four blades while the furnace temperature is maintained. You can increase this as you feel is needed.