To harden the knife, make a few metal plates to conduct experiments. Heat the first plate irregularly from minimum to maximum temperature and put in water or oil. In the grip start breaking plate and to break find you need to size the grain. If the grain at the bend, the metal will have poor cutting quality, kink should have a coarse surface. For example, consider the fracture of a large file, around the perimeter he will have a smooth fracture, but in the heart already will have the desired grained surface. After this experience, you determine the desired temperature for heating.
Now you need to choose the medium for quenching. Hardened in water, oil, nitrogen, and even use mercury. After the heat of the plate should be lowered into the oil, whose temperature is 200°, withstand of 15 minutes to 2 hours, and then put it in cold water. Sometimes for quenching even use liquid lead.
Environment for hardening can be alternated by double tempering or conditioning. Continue with your research. Take a plate, heat it to the desired temperature, make the hardened to such strength that the plate could break the grip if it is to decline at a 30 degree angle from vertical, then release make this disc might break if 45градусах. Using this method, you will get high strength and good cutting properties.
Some General rules: a blade before quenching it is necessary to anneal, then there will be fewer cracks. Do heat slowly, evenly and longer. Use muffle furnace adjustment. For hard quenching into liquid immerse the blade vertically and hold it steady. If you do the annealing in different environments, the knife will last longer.
Advice 2 : How to temper steel for a knife
To make a regular stainless steel knife more durable, it can be tempered. The hardening process is also called vacation. At a certain skill, a vacation can be done at home. How to correctly temper the knife and to increase the strength of the blade?
You will need
- - knife for quenching;
- - muffle oven;
- the oil (antifreeze, automobile engine oil, testing);
- - material for polishing, chrome-plating steel.
Preheat muffle furnace to a temperature of 1030-1050°C. once onepiece to reach the required temperature, soak it in the on position, the hour and turn off. The temperature in the furnace should be strictly up to 1100°C, or when the calcination will undergo an irreversible process of consolidation sorbitol steel structure. It becomes viscous and loses its impact properties.
Place the knife blade in the oven. You must first remove the handle, high temperature, almost 100% deform the material of the handle. Time for a high holiday of the blade is calculated as 10 minutes per 1 mm thickness. Visually determine the degree of calcination by the color of the blade. It needs to be the same as the color of the inside of the furnace.
Remove the blade from the furnace and vertically immerse it in a container of oil, slightly ' s along the blade to the profile of the blade does not lead from excessive pressure on the soft hot steel.
Having waited until the steel temperature falls to 300°C (bluish color on the steel surface), place the blade in the muffle furnace, the pre-exposed temperature of 200-300°C. the Process low vacation should last 3-4 hours.
Remove the blade from the furnace, if necessary, send it, let it cool in a natural environment outdoors.
Polish, othererwise, sharpen the blade, attach it to the handle.
Never attempt to align the blade after high-temperature tempering - blade due to the high sorption of steel is very brittle and conventional mechanical exposure can lead to cracking of steel. Straightening can only be performed after low tempering at temperature up to 300°C.
For low tempering after high-temperature muffle furnace nekalki will be a very long time to cool, so as not to interrupt the tempering process and not seek a second muffle furnace can be an ordinary kitchen oven to heat to a temperature of 250-300°C and to conduct low leave it.