METAL PROCESSING (BORING, HEAT TREATMENT)
Coordinate-boring work
A wide variety of technologies are used for machining metals. Coordinate-boring is one of their varieties, which is the final stage of this type of machining of workpieces. For quality results, boring, drilling and milling techniques are used with different degrees of accuracy.
A wide variety of technologies are used for machining metals. Coordinate-boring is one of their varieties, which is the final stage of this type of machining of workpieces. For quality results, boring, drilling and milling techniques are used with different degrees of accuracy.
Classified by two types of this plan of work: machining horizontal-boring, vertical-boring. They are performed on holes obtained by casting. The purpose of boring operations is to enlarge a given hole, increase its size and achieve a certain diameter. This also eliminates the surface roughness of the workpiece.
The performance of work on specialized boring machines operating at low speeds makes it possible to obtain high-precision, down to tenths of a millimeter in the result.
Despite the similarity of coordinate boring processes with drilling and milling, their main feature is the ability to perform unique operations.
Such as:
– High-precision machining in grooves;
– Obtaining tapered holes;
– Milling at different angles.
And as related work are: drilling holes, finish milling the ends, marking, checking intercenter and countersinking holes.
And as related work are: drilling holes, finish milling the ends, marking, checking intercenter and countersinking holes.
Special machine equipment used in coordinate boring operations has a number of advantages. As a rule, machines are equipped with rotary tables, which allow performing operations with high accuracy:
- Machining of holes specified in a polar coordinate system;
- Operations in inclined surfaces;
- Perpendicular holes;
- Countersinking of end holes.
Additional digital indications on the machines help to clearly and accurately set the coordinates for certain operations.
Center-to-center distances can be set to an accuracy of 0.004 mm in the coordinate system, and the accuracy between axes is 0.006 mm.
Thermal metalworking
Heat treatment of metals is a technological process that is an essential step in the manufacture of parts made of carbon and alloy steels. It always has a positive effect on the performance qualities of the metal, respectively the finished product. It is used to obtain higher parameters of strength, hardness, wear resistance, elasticity, or on the contrary, softness, malleability.
There are three main types of heat treatment:
– Annealing
– Normalization .
– Tempering.
The first is a high-temperature metalworking technique. First the alloy is heated to a certain high temperature, then it is kept for some time and subjected to a slow gradual cooling. The purpose of annealing is to level the structure of the metal, improving its ductility and relieving stress.
Annealing is divided into several types: first type, diffuse, second type, complete and incomplete, spheroidizing, isometric, recrystallization, light. Each of them makes it possible to achieve certain structural changes in the metal, bringing it to the desired state.
Normalization is a high-temperature treatment of the metal. The steel is heated 30-50 degrees above the temperature of the upper critical points of AC3 or ACm. Then the product is subjected to cooling, which takes place slowly outdoors. The normalization process has two purposes: the first is the elimination of hardening and the second is the removal of internal stress. Normalization is mainly carried out on carbon and low carbon steels. The result of the process is a fine-grained structure of the metal.
Quenching is necessary when you want to give the metal hardness and strength. Unlike normalization, the cooling stage takes place at high speed, in water, oil or other liquids. The process results in a hardened material with a nonequilibrium structure.
The heat treatment of metals has a number of positive characteristics. Among the main ones: increasing the wear resistance of products, reducing rejects in the manufacture of parts, tools, saving on new products by increasing the strength of the alloy used to make parts.
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