First of all, products are classified in terms of their heat treatment techniques and transferred to the heat treatment workshop. Products that are sent into the furnace shall not exceed 1/3 of volume of the furnace. All the information, e.g. The date, should be kept down in record. Products and test bars of the same charge number are treated with the same techniques in the same furnace. All the test bars should be numbered with product names and material designations and then are sent to test their physical properties.