Servo valve components are: valve body, valve cover, the main valve and vice valve spool, feedback lever, feedback spring and fork, the median adjustment lever, lock nut and so on. Servo valve on the common fault, Tianjin, heat-conducting oil pump manufacturers as follows: A: The main cylinder offset cylinder. Symptom: Two cylinders are synchronized one after the other until the hold-up cylinder processing methods: Loosen the lock nut adjust the rod to observe the movement of the piston rod in the tank slows down, slow down, continue to screw clockwise until the piston Rod stopped. If it becomes faster, tighten the bolt counterclockwise until the piston rod stops. Two: spring break. Symptoms: pumping speed can not be adjusted to the fastest speed of pumping. When the pumping pressure is high, the engine may be decelerated.
Approach: replace the spring.
Three: spool stuck. Symptoms: There is no pumping or both sides of the cylinder speed is different, may also hold the cylinder. Treatment: cleaning spool or grinding. Four: the lever broken or bent Fault phenomenon: the pumping speed can not be adjusted to the fastest speed of pumping. Pumping pressure is high, the engine may be out of speed, or on both sides of the cylinder speed is different. Remedy: Replace the feedback lever. An oil pump is a lightweight and compact pump, and proposes an oil pump having a housing made of an aluminum-containing material and a movable mold member provided in the housing, wherein the movable mold member Made at least partially of a sinterable iron-based alloy comprising at least one austenite, and wherein the molded article made of a sinterable material has a coefficient of thermal expansion 60% of the thermal expansion coefficient.
The Hardness Tester is a hardness tester. Metal hardness measurements were first defined by Ray Ommel's definition of hardness, which means that the material resists the ability of a hard object to press into its surface. It is one of the important performance indicators of metal materials. The higher the hardness in general, the better the abrasion resistance.
Hardness test is the simplest and most convenient test method in mechanical performance test. In order to be able to replace certain mechanical properties tests with hardness tests, a more accurate conversion of hardness and strength is required in production.
1. Dietmar Leeb The Leeb hardness is based on the latest Leeb hardness test principle and is designed using state-of-the-art microprocessor technology.
2. Brinell Hardness (HB) Hardened steel balls of a certain size (typically 10 mm in diameter) are pressed onto the surface of the material at a given load (typically 3000 kg) and held for a period of time. After loading, the ratio of the load to its indentation area , which is the Brinell hardness value (HB) in kilograms force/mm2 (N/mm2).
3. Rockwell Hardness (HR) When HB>450 or the specimen is too small, the Brinell hardness test cannot be used instead. It uses a diamond cone with a vertex angle of 120° or a steel ball with a diameter of 1.59 and 3.18 mm to press the surface of the material under test under a certain load. The hardness of the material is obtained from the depth of the indentation. According to the hardness of the test material, divided into three different situations
HRA: It is the hardness obtained with a 60kg load and a diamond cone press. It is used for materials with extremely high hardness (such as cemented carbide, etc.).
HRB: Hardened steel balls with a load of 100kg and a diameter of 1.58mm are used to obtain a hardness that is used for materials with low hardness (such as annealed steel, cast iron, etc.).
HRC: It is the hardness obtained with a 150kg load and a diamond cone press. It is used for materials with high hardness (such as quenched steel, etc.).
4. Vickers hardness (HV) with a load of 120kg or less and a diamond square cone press with a vertex angle of 136° is pressed into the surface of the material. The load value is divided by the surface area of the material indentation pit, which is the Vickers hardness value. (HV).
5 Knoop Hardness (HK)
Suitable for hardness testing of high hardness materials (general hardness measurement above HV1000 hardness).
6. There are Shore hardness tester
7. Wechsler hardness tester (HW)
Suitable for the measurement of Vickers hardness value of aluminum alloy products.
8 plaster hardness tester
Applicable to the measurement of the hardness of building plaster, the steel ball is placed on the test piece, and the depth of the ball mark under the effect of the fixed load is measured, and the plaster hardness of the test piece is calculated.
The above hardness is only a few commonly used, in addition to Shore hardness, Shore hardness, Barcol hardness, Mohs hardness. Practice has shown that there is an approximate correlation between hardness values and strength values between various hardness values of metallic materials. Because the hardness value is determined by the resistance to initial plastic deformation and the resistance to continued plastic deformation, the higher the strength of the material, the higher the resistance to plastic deformation and the higher the hardness value.
Hardness Tester
Hardness Tester,Automatic Hardness Tester,Digital Hardness Tester,Vicker Hardness Tester
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