Problems Existing in Popularization of Thermal Spraying Technology

       Recently, there have been a lot of consultation calls from all walks of life. Facing the questions and concerns of customers, I will make a summary here.



1. Most of the customers do not know much about the thermal spraying process and think that the thicker the better. Anything is too much. For different products and different requirements, the thickness varies from 0.05 to 0.5. I have sprayed the thickest 1.5 mm, but it is only a special case. I suggest that the thickness should not exceed 0.3.



2. The bonding strength of thermal spraying is not high. This bond strength is only relative, not an absolute concept. Using high-performance supersonic spraying equipment, the bond strength is at least greater than 60MPa. What is this concept? 1MPa=10kg/cm2, which means that each square centimeter can withstand a tensile force of 600 kg, so in general, such a bonding strength is sufficient. The biggest problem is that the thermal spray coating is brittle. For the same nickel-based alloy, the toughness of the coating made by spray welding and spraying is very different, which is determined by the process itself. Therefore, the thermal spray coating cannot be impacted. It is not a problem of hardness or bonding strength, but a problem of the process itself.



3. Thermal spray is too expensive. The reason for the high price is:



1) The price of raw materials is high. The prices of raw materials with the same ingredients in the market will be very different. We use domestic brand products with strict control of ingredients, stable quality and high prices.



2) The powder application rate is low during powder spraying. Some people say that you are not using imported equipment, why is the deposition rate low. Because the flame flow of the imported equipment spray gun is fast and the rebound is serious, the deposition rate is lower than that of the domestic equipment.



3) The use cost is high. Imported equipment uses oxygen and aviation kerosene, and the cost per hour is much higher than domestic equipment.



4) Accessories are expensive. All imported equipment accessories are also imported, and the loss of accessories is also higher than that of domestic equipment.



5) High labor cost. Our employees need more skills, not only to operate spray equipment, but also to program robots.



6) Equipment depreciation is high. Imported equipment plus robots is close to 2 million, and many domestic equipment will not be equipped with robots, which are less than 100,000.



Therefore, the cost of using imported equipment is higher than that of domestic equipment. Many low-end products only need domestic equipment, and more products need imported equipment to meet the requirements.



4. Low-end spraying companies have caused bad consequences. Some customers have used spraying before, but because of this industry is a mixed bag. Some spraying companies do not have advanced equipment and excellent technology, and they brag too much about the performance of the coating. As a result, they cannot meet the application requirements at all, causing many customers to directly suspect that it is a technical problem. Some domestic spraying equipment has very poor performance. The same tungsten carbide coating has a bonding strength of only more than 20 MPa and a hardness of only HV800. The wear resistance of such a tungsten carbide coating is not as good as that of nickel-based alloys.



5. The customer can't accept the price, and the spraying company reduces the price in order to receive the order, but can only reduce the quality in order to obtain profit. Everyone understands that you get what you pay for, and some customers just like to keep their prices down. We all understand the consequences of this, and such consequences are passed on to customers and affect their use. The customer's use effect is not good, and they suspect that it is a technical problem. In fact, the bottom line is that the money is not in place. Similarly, tungsten carbide is sprayed. There are 2,000 yuan a square, and 12,000 a square. If you choose 2,000 a square and you need to ensure the quality, this is a joke.



6. Thermal spray technology is not a panacea, and not all products can be used. Although thermal spraying technology has a wide range of applications and strong applicability, it cannot be used in some working conditions. Thin-walled parts, small parts, sharp edges, and impacted parts are not suitable for spraying.