SU954867A2

SU954867A2 - Magnetic powder checking method

Info

Publication number: SU954867A2
Application number: SU802926922A
Authority: SU
Inventors: Борис Александрович Кадышкин; Моисей Элозорович Хургин
Original assignee: За витель
Priority date: 1980-05-20
Filing date: 1980-05-20
Publication date: 1982-08-30

Description

1one

Изобретение относитс к неразрушающему контролю высокоуглероцистых и конструктивных цементированных сталей и может быть использовано в любой отрасли машиностроени .The invention relates to non-destructive testing of high-carbon and structural cemented steels and can be used in any branch of engineering.

По основному авт. св. № 51О669According to the main author. St. № 51О669

известен способ контрол заключающийс в том, что контролируемую деталь намагничивают , нанос т на ее поверхность магнитный порошок и осматривают ij .,QA method of control is known in that the test piece is magnetized, a magnetic powder is deposited on its surface and inspect ij., Q

Недостатком известного . способа вл етс невозможность вы влени частиц карбида железа (цементита), которые при неправильно проведенном технологическом процессе могут выдел тьс в виде ,5 карбидной сетки на поверхности издели .The disadvantage of the famous. The method is the impossibility of detecting particles of iron carbide (cementite), which, if improperly carried out by the technological process, can be released in the form of, 5 carbide mesh on the surface of the product.

Цель изобретени обеспечение возможности вы влени част1ш цементита.The purpose of the invention is the possibility of detecting part of cementite.

Поставленна пепь достигаетс тем, что контролируемое изделие перед навесе- 20 нием магнитного порошка нагревают до температуры 120-220 С.The delivered ash is achieved by the fact that the controlled product is heated to a temperature of 120-220 ° C before the magnetic powder is loaded.

Способ, облада низкой трудоемкостью, позвол ет обнаруживать карбидную полоочатость или сетку на контролируемой поверхности издели . Способ основан на том, что точка Кюри цементита близка к 21О С и выше этой температуры цементит неферромагннтен, а ниже - ферромагнитен.The method, which has low labor intensity, makes it possible to detect carbide hollowness or a mesh on a controlled surface of the product. The method is based on the fact that the Curie point of cementite is close to 21 ° C and above this temperature the cementite is non-ferromagnetic, and below it is ferromagnetic.

При температурах близких к точке Кюри намагниченность его весьма низка и значительно ниже намагниченности мар тенсита .At temperatures close to the Curie point, its magnetization is very low and well below the martensite magnetization.

Так, значение намагниченности насыщени мартенсита и цементита по отношению к намагниченности мартенсита, составл ет, %:Thus, the value of the saturation magnetization of martensite and cementite with respect to the magnetization of martensite is,%:

Температура, с 27 127 177 227 Мфтенсит1ОО 98 97 95Temperature, from 27 127 177 227 Мфенсит1ОО 98 97 95

Цементит 60 5О 4О ОCementite 60 5O 4O

Способ осуществл етс следующим образом .The method is carried out as follows.

Claims

The controlled product is magnetized by lime using the M method, heated to a temperature of 12 ° –220 ° C, treated at this temperature with a magnetic powder, and then inspected with a scattering mark. the surface of the lei e magggnogo powder on the product. Magnetic powder should be applied dry. A mineral oil based magnetic suspension can also be used. In order to avoid excessive cooling of the product with a magnetic suspension, the latter follows. Previously, the temperature should be heated. The specified temperature range of the product is selected from the following considerations. When the product temperature is less than 120 ° C, the difference in the magnetizations of martensite and cementite is also insufficient to effectively detect particles of cementite. At a temperature of 220s, the magnetization of MapTeHCHfia is 95% of the magnetization at a constant temperature, which is still permissible according to GOST 2110 5-7 5. At temperatures above 220 ° C, undesirable occurrences of a decrease in the hardness of martensite and its magnetostriction begin, with zero magnetization of cementite. Example. The controlled product gear from steel 12X2H4A, tucked cementation, heat treatment and machining of the surface, 74 is magnetised with a current of 8OOO-1OOOO A, is placed in an oven with a temperature of 150170 ° C, and is kept up to warm-up. Then removed from the oven, placed on the control table and watered magnetic. with a temperature of 10 ° -120 ° C and composition: MS-20 oil - 5O%, transformer oil - 50%, ferrous oxide-ferrite magnetic powder - 2O-30 g / l, incubated for slurry formation, sedimentation of magnetic powder particles and cooling the part, after which osmatr vayut. Invention Magnetic powder control method according to aut. St. No. 510669, distinguished by the fact that, in order to make it possible to detect cementite particles, the product is heated to a temperature of 120-220 C before applying the magnetic powder. JWcT04: HKKH information taken into account during the examination 1. USSR author's certificate No. 510669 , cl. Q 01 N 27/84, 1972 (prototype).