Some time ago, Steven, from a Hydraulic Valve Company in UK, fell in a batch of hydraulic directional valves purchased in Ningbo. There had some email communication between AAK HYDRAULIC VALVE and Steven, but maybe the fate has not yet arrived, we did not cooperate until last month this year. Steven regained his confidence because he had suffered a waterloo and got back a key game here in AAK.
At the beginning of this year, a batch of hydraulic directional valves purchased by Steven in Ningbo were stuck and failed during the test run, resulting in the failure of the whole batch of equipment to start up and run. His customer asked UK company to solve it within 30 days, otherwise there will be a big claim. Steven informed the original hydraulic valve manufacturer of these conditions, but the manufacturer prevaricated that it was a problem caused during the assembly process and had no direct relationship with them. Steven also consulted other hydraulic valve manufacturers. They either replied that the hydraulic valve was not produced by them and could not give the corresponding strategy, or there was no reply. Steven received serious rebuff here and there, and feel stressed.
When Steven contacted AAK HYDRAULIC VALVE, we were willing to cooperate with him to solve this problem because we felt his trust in AAK HYDRAULIC VALVE. Through his email description, we were still not sure what the problem is, and asked him to send us samples.
After AAK HYDRAULIC VALVE received the hydraulic directional valve samples from Steven, we felt that the relative sliding between the middle valve column and the valve body was not smooth. When the whole hydraulic directional valve is disassembled, there are slight scratches on the column surface, the valve body hole has a negative tolerance, and the valve body column hole has plastic distortion. Further microscopic examination showed that the surface of the material was etched badly. It is certain that the original hydraulic valve manufacturer has problems in material selection and heat treatment of alloy steel. Then we informed Steven of the result in a report and attached our suggestions for this style of hydraulic directional valve.
After receiving the report, Steven seemed to see hope and asked us to make 5 hydraulic directional valve samples for his customer to run successfully first. After knowing the working conditions of this hydraulic directional valve, we adjusted the material selection of alloy steel, and increased the overall hardness of the hydraulic directional valve by 30% on the original basis.
1 week after Steven received the samples, he informed AAK HYDRAULIC VALVE by e-mail that the hydraulic directional valve samples made by AAK were started up smoothly as soon as they were tested on the machine. When the new delivery date and order quantity were confirmed by his customers, he was finally relieved. At the same time, he wanted to know how AAK would produce each hydraulic directional valve of the same quality as these samples in mass production.
In terms of material selection, according to the working conditions of hydraulic valve, AAK HYDRAULIC VALVE set the material composition requirements with computer program, and then use metallographic sample for comparative analysis to detect the selected alloy steel. For the heat treatment of alloy steel, the same batch of steel shall be heat treated at the same time, without splitting batch or section. In terms of quenching and carburizing, the carburizing gas composition of alloy steel is changed according to the aging temperature and holding time of the process, and the carburized alloy steel is controlled not to retain excessive austenite during heat treatment, so as to ensure the stability of the whole alloy steel. AAK can achieve the aging temperature of 420 ℃ and thermal insulation of more than 10h. Basically, more than 95% of the hydraulic valve manufacturers can not meet this process index.
After Steven got AAK's reply, he finally put down the heart that was uneasy for more than 20 days. The owner appreciated that he solved the difficulty on the hydraulic directional valve order within the time specified by the customer, and gave him a week's holiday to relax.