Bar Rod magnets AlNiCo, Deep Pot Holding, steel body with Threaded Neck, Male Thread, galvanized, Rod magnet AlNiCo (Aluminum Nickel Cobalt) with metal pot and external thread.
Magnet ID:              ADPET-6365
Material: Circular rods made of precision-cast AINiCo 500 and steel body
Plating / Coating:  galvanized        
Shape:         Bar / Rod  with External  Thread
Tolerance:           D ±0.1 mm / H ±0.2 mm
Magnetisation Direction:    anisotrop
Maximum Operation Temperature: 450 °C 
Delivery Time:           14-35 days
Article number         D mm                H mm           Thread MxL      Force* N     Weight g      Temperature °C    
ADPET-6365         63(+0.1/-0.1)     65(+0.2/-0.2)            M12x20                 660                  1293                   450        
Measurements:

These magnets are very tough - they do not chip or crack or break easily when:
             dropped onto a hard surface
             allowed to smash together with another alnico magnet
             allowed to smash together with a piece of metal
             struck with a hammer or other hard substance
You still have to be prepared to have the force of attraction increase quickly and dramatically as the North pole of one gets closer to the South pole of the other.  Magnets made of alnico are usually cast in a mold and then magnetized.
b.  Heat
Heat is another strength for alnico magnets.
Their maximum working temperature is 540 degrees C (1004 degrees F).
 The Curie Temperature for alnico magnets is a blistering 860C (1580F).
Hot temperatures are not going to affect these magnets much!