The service life and strength depend on the quality of hardening of an iron product. If the hardening of a steel tool or household item is insufficient, it can be hardened at home.
- - bonfire;
- - charcoal or coal;
- - a container with machine oil (diesel, motor or autol);
- - a container with well water;
- - ticks.
Light a fire with a large amount of charcoal or coal. This is necessary in order to maintain a high temperature inside the fire. For each grade of iron there is a certain quenching temperature; if the iron is not heated sufficiently, quenching will be useless. Therefore, check that the coals are hot enough and that the tedious temperature is reached. To do this, put a metal rod on the coals and watch the color change process. When the rod turns to the color of coals, the desired temperature has been reached.
Place a piece of iron on the fire. Carefully control the entire hardening process. Flip the product from one side to the other from time to time. Do not allow the hardening site to turn white, this is a sign of overheating of iron, which is unacceptable when finishing the metal before hardening. In order for the iron product to be well hardened, the hardening site must be crimson. Make sure that the color of the hardened area is uniform without dark areas. This will avoid cracks on the hardened product.
As soon as the color has become bright, take out the product with the help of pliers and dip it into a container of oil. For three to four seconds, hold the product in the container, stirring the oil, and suddenly take it out into the air. Wait two seconds and dip again in a container of oil. Continue this procedure until the color of the place of hardening becomes "cyanotic".
As soon as the place of quenching has acquired a cyanotic color, remove the product from the oil and dip it into a container of water. Leave the product in water until it cools completely.