Alnico Magnets are traditionally classified using numbers assigned by the Magnetic Materials Producers Association (MMPA), for example, Alnico 3 or Alnico 5. Cast Alnico Magnet Cast Alnico Magnet,Cast Alnico Block Magnet,Cast Sintered Alnico Magnet,Strong Cast Alnico Pot Magnet Jinyu Magnet (Ningbo) Co., Ltd. , http://www.magnetbonwin.com
The principle of the Martindale wear tester is that under the specified pressure, circular samples are subjected to circular plane motional rubbing using the movement path of the LISSAJOUS. The figure shows that the two vibration directions are perpendicular to each other and the frequency is a simple integer. The simpler harmonic motion trajectory. The rub resistance performance is characterized by the cycle time at which the specimen is broken. Damage refers to the penetration of a hole in the test sample.
The Martindale wear tester uses the Martindale wear tester described in EN ISO 12947-1. The total mass of the load block and specimen holder assembly shall be (595 ± 7) g to ensure that the test specimen is subjected to (9 ± 0.2) kPa pressure during the test.
The glove cut index tester cuts the sample back and forth through a circular blade that reciprocates under a fixed load until it is cut through; this test is not applicable to gloves made of a very hard material, such as a metal chain ring glove.
Glove resistant cutting index tester blade should be applied (5 ± 0.05) N pressure of the object; blade sine maximum cutting speed of 10 cm / s;
The tear resistance tester measures the force required to tear a rectangular sample in the direction of a half opening in the length direction; the instrument must be a low inertial force measurement system. The tear resistance tester records the tear force at a tensile speed of (100±10) mm/min.
The tear resistance of each sample was recorded as the highest value it could achieve, and the tear resistance rating of the glove was determined by the lowest value of the four test results. The sample should be completely torn. If the specimen has not been completely torn by more than 75 N force, the test can be stopped and the maximum force achieved can be recorded.
The glove puncture resistance tester is a force required to pierce a fixed test specimen with a certain size of a steel needle. This is different from puncturing with tiny needles or other sharp objects. Glove resistant puncture tester must be able to measure 0 ~ 500N force; must be low inertial compression; test steel needle must meet the standard requirements.
The glove puncture resistance tester moves the steel needle down to the test specimen at a speed of 100 mm/min until the displacement relative to the specimen reaches 50 mm. Record the maximum value of this force, even if the sample has not yet been penetrated.
Alnico magnets are produced by casting or sintering processes.[8] Anisotropic alnico magnets are oriented by heating above a critical temperature and cooling in the presence of a magnetic field. Both isotropic and anisotropic alnico require proper heat treatment to develop optimal magnetic properties-without it alnico's coercivity is about 10 Oe, comparable to technical iron, which is a soft magnetic material. After the heat treatment alnico becomes a composite material, named "precipitation material"-it consists of iron- and cobalt-rich[9] precipitates in rich-NiAl matrix.
Alnico's anisotropy is oriented along the desired magnetic axis by applying an external magnetic field to it during the precipitate particle nucleation, which occurs when cooling from 900 °C (1,650 °F) to 800 °C (1,470 °F), near the Curie point. Without an external field there are local anisotropies of different orientations due to spontaneous magnetization. The precipitate structure is a "barrier" against magnetization changes, as it prefers few magnetization states requiring much energy to get the material into any intermediate state. Also, a weak magnetic field shifts the magnetization of the matrix phase only and is reversible.
Alnico magnets are ideal for high temperature applications up to 550ºC
. Cast Alnico Magnet is very stable, has good corrosion resistance and a typical hardness of 50 Rockwell C. Once cast, the material is so hard that the only machining possible is grinding
. Cast Alnico Magnet represents the most versatile magnet material available. The range of properties can be accurately designed for specific applications by changes to element analysis and heat treatment.
EN388 protective gloves performance tester
EN388 protective gloves performance tester includes Martindale wear tester, glove cut index tester, glove tear resistance tester, glove puncture resistance tester and so on.