On 2018-08-08 14:48:54
Treatment technology of large workpieces in trolley furnace
The cooling process of large workpieces processed by trolley furnace includes tempering cooling process, quenching cooling process and normalizing cooling process.
1. Trolley furnace annealing and cooling process: annealing refers to the heat treatment process that the workpiece is heated to a proper temperature, kept for a certain time, and then cooled slowly. Annealing cooling usually takes the way of furnace cooling to about 200 ℃;
2. Tempering cooling process: the tempering cooling is relatively complex. For materials without high temperature tempering brittleness, such as 35, 45, 55, 35CrMo steel, air cooling is adopted;
For materials with high temperature temper embrittlement, such as 40Cr, 42CrMo, 35SiMn, 50simn65mn, 40CrNiMo, 3cr13cr13cr13 steel, air cooling can be used when the low temperature temper is less than 400 ℃, and water cooling or oil cooling must be used when the high temperature temper is greater than 450 ℃, to avoid temper embrittlement, so temper cooling is particularly important for Quenched and tempered parts, and the process must be carefully formulated.
The steps of large workpieces treatment in the trolley furnace
With the development of China's economy, various industries have been affected. The trolley furnace is a kind of energy-saving facility with administrative division and standard. In the near future, the whole iron machinery will be hot solved. Do you understand the freezing process of the trolley furnace? The above small edition is for your detailed notes. This is followed by the description of "icing process and technical parameters for trolley furnace".
1. Cold straightening of trolley furnace
1) Before straightening, it is necessary to check the working drawing clearly, see clearly the technical conditions such as hardness, remove the contamination of the hole, and measure whether there is deviation of the hole.
2) , the normal hardness of the bar type work piece is less than 40 HRC, and the convex surface of the bar type work piece is cold pressed at room temperature; the concave surface of the bar type work piece is cold pressed above 40 HRC.
3) The plate-shaped parts with normal hardness above 40 HRC shall be cold straightened, and the thin plate with hardness above 40 HRC can be hammered on the side.
4) . when cold striking the concave, choose the suitable hardness hammer, and be careful not to knock the hot solution furnace parts into deep dents.
5) Cold blow should be selected in non critical parts of the work piece.
2. Constant temperature straightening of trolley furnace
1) , normal isothermal, cold press the convex surface on the rack hand press.
2) For the diameter larger than 16mm, when the above steps are effective, it is allowed to heat the drill groove to more than 560 ℃ and press it on the electric drill hand press.
3) , the isothermal swing difference is controlled at 0.15mm.
4) . when brittle, the straightening should be maintained.
3. Hot straightening of trolley furnace
1) , as for broach, press cutter, large diameter drill, milling cutter rod and scissor blade, they are normally straightened by quenching.
2) , high speed tools, the temperature of stop calibration is slightly higher than that of room temperature.
3) The heat stopping temperature of carbon steel and low alloy steel is about 80 ℃.
4) . during hot calibration, measure carefully to prevent dead bend and two bends.
4. Hot straightening of trolley furnace
1) The work piece of quenching and hot straightening shall continue to be heated and straightened normally.
2) . hot pressing convex surface of high speed tools after tempering.
3) , carbon steel, low alloy steel after tempering hot pressing convex or while hot with a sharp hammer hit concave.
4) . the thin plate work piece shall be back heated and straightened. It can be fastened and tempered by pressing plate. After thorough burning, it shall be stored and pressurized again. After thorough pressing, it shall be kept fresh for a period of time.
5) . for long parts that are not easy to straighten, such as broaches, the two convex faces can be pressed together, then the tempering can be continued and stored, and then the pressure can be removed after being cooled to room temperature.
6) About the straight shank bit, it can be pressed and tempered with △ shaped tempering tenon.
5. Hot baking and straightening of trolley furnace
1) The high-speed tools tempered in the tempering furnace shall be straightened by hot baking and heated by gas and atmosphere.
2) . the hot baking part shall be selected from the non operation part or non critical part, and the heat degree of hot baking shall be no more than 700 ℃; when the key part is hot baking, the heat degree shall be no more than 560 ℃.
3) . after hot baking and cold to room temperature, it shall continue to be recalibrated.
6. Hot spot straightening of trolley furnace
1) Hot spot straightening of pyrolyzing furnace is normally used in carbon steel and low alloy steel. Oxygen acetylene gas or oxygen gas is used to continue hot spot straightening in the convex part of the work piece. Carbon iron is water-cooled and low alloy steel is oil-cooled or air-cooled.
2) The heat of hot spot straightening depends on the work piece data, hot spot status and winding status, but be careful not to burn the work piece in name or form quenching cracks.
3) Hot spot position should be the main position of the work.
4) As for the simple or heavy-duty parts of alloy steel, the sea area around the hot spot shall be preheated with a flame before the hot spot. The preheating heat is not as hot as the tempering heat. After the hot spot, the joint shall be aligned and tempered at high temperature.