The main process characteristics of geological drilling pipes

When any equipment or product is produced, it will have different production processes and play different roles in the production process at the same time.For example, geological drilling pipe, its main process flow is simply like this: electric arc furnace initial refining-out-of-furnace refining-billet continuous casting-pipe billet rolling-pipe billet perforation-waste pipe heat treatment-steel pipe cold drawing-finished product heat treatment-steel pipe correction-acceptance-packaging and warehousing.It's pretty simple to watch the production process, isn't it?In fact, in practice, many precautions and problems are waiting for us.Next, let's talk about the characteristics of the main process of this product.

1. The 42MnMo7 steelmaking process of the main process：

The key to 42MnMo7 smelting is composition control. Reducing the content of harmful impurities and gases is to avoid segregation in the billet. Therefore, the following requirements are made for the smelting process.：

(1) Pay attention to controlling the oxygen blowing intensity during the melting process to ensure that the melted carbon is greater than 0. 50%, the terminal carbon is greater than 0. 20%;

(2) Due to the large amount of ferromanganese added, in order to prevent the increase of ferromanganese from causing P to exceed the standard, the steel discharge P of the initial refining furnace is ≤0.10%, and the steel discharge temperature is greater than 1640℃.;

(3) Iron niobium is added to the steel flow at a recovery rate of 95%;

(4) Hanging package temperature: the first package is 1580-1590℃, and the renewal package is 1560-1570℃.

2. Pipe billet rolling of the main process of geological drilling pipe：

42MnMo7 is a medium-carbon Bainite series steel, with a certain amount of Nb added. The addition of Nb can prevent the growth of the original austenitic grains during the heating of the billet.Taking into account the solid solution of Nb into the austenite and ensuring rolling in the recrystalline area, the heating temperature is set to 1180-1220℃.The purpose of controlling the final rolling temperature is to refine the grain and prevent the plasticity of the tube billet from deteriorating. A large number of studies have shown that by rolling near the critical temperature of the austenite, due to the decrease in deformation temperature, the recrystalline capacity of the austenite is weak, and the austenite crystals are stretched and stretched. At the same time, the dislocations and other defects caused by the deformation process are not easy to disappear, so it provides a large number of nucleation positions, high nucleation rate, and good toughness of grain-refined steel.In the rolling process control, it is determined that the final rolling temperature is Ar3+(50-100)℃, about 820-870℃.

3. Perforation of the tube billet of the main process：

(1) Blank inspection—cutting and cutting-oblique bottom furnace heating—two-roll oblique rolling perforation

(2) The tube billet is heated at a low temperature and slow speed, the heating and baking temperature is controlled at 1220-1240℃, the heating time is 50-60min, the rolling rhythm is controlled at 3 pcs/min, and the number of fabrics in the furnace is maintained at more than 150 pcs.

4. Cold drawing of the main process：

After the waste pipe is annealed, pickled, and lubricated to remove internal stress, it is placed for 2-3 days to remove hydrogen embrittlement, and then the finished product is drawn on a 75t chain cold drawing machine.

Are the main process characteristics of the above geological drilling pipes not well understood?Its theoretical knowledge is indeed a bit difficult to understand, but if it is used to play a role, it will be a very big and important role.Of course, in the process of cold-drawing the product, try to avoid cracks, cracks, unplugging and other problems, then the success rate of the refining results will be great.