SU1276468A1

SU1276468A1 - Method of testing spot welds for static vibration strength

Info

Publication number: SU1276468A1
Application number: SU843737707A
Authority: SU
Inventors: Виктор Александрович Попковский; Валерий Петрович Березиенко; Владимир Мечиславович Порукевич; Анатолий Дмитриевич Ковтун; Ольга Васильевна Иванина
Original assignee: Могилевский Машиностроительный Институт
Priority date: 1984-03-01
Filing date: 1984-03-01
Publication date: 1986-12-15

Abstract

Изобретение относитс к сварке, в частности к способам определени статической и вибрационной прочности сварных соединений, и может найти применение в.машиностроении при исследовании прочности соединений, работающих на срез и скручивание. Целью изобретени вл етс расширение технологических возможностей образца путем обеспечени сложно напр женного состо ни в сварной точке. Образец дл определени статической и вибрационной прочности сварного соединени изготавливают контактной точечной сваркой из двух пластин равной длины и пр моугольной формы, расположенных друг на друге. На противоположных концах каждой пластины расположены сварна точка и отверстие, центры которых лежат на оси симметрии пластины . Рассто ние между последними составл ет The invention relates to welding, in particular, to methods for determining the static and vibration strength of welded joints, and can find application in mechanical engineering in the study of the strength of joints working on shear and twisting. The aim of the invention is to expand the technological capabilities of the sample by providing a difficult stress state at the weld point. A sample for determining the static and vibration strength of a welded joint is made by resistance spot welding of two plates of equal length and rectangular shape, stacked on top of each other. At the opposite ends of each plate there is a welded point and a hole, the centers of which lie on the axis of symmetry of the plate. The distance between the latter is

Description

Изобретение относится к области исследования прочностных свойств материалов и соединений, а именно к способам определения статической и вибрационной прочности сварных соединений, работающих на срез и скручивание, особенно в условиях преобладания напряжений среза, например, узлов сельхозмашин.The invention relates to the field of research of the strength properties of materials and joints, and in particular to methods for determining the static and vibrational strength of welded joints working on shear and twisting, especially in conditions of prevailing shear stresses, for example, nodes of agricultural machines.

Целью изобретения является расширение технологических возможностей путем обеспечения сложнонапряженного состояния в сварной точке.The aim of the invention is the expansion of technological capabilities by providing a difficult state at the weld point.

На фиг. 1 представлена схема испытаний; на фиг. 2 - закрепление образца в приспособлений.In FIG. 1 is a test chart; in FIG. 2 - fixing the sample in devices.

Способ осуществляют следующим образом.The method is as follows.

Сваривают образец для определения статической ц вибрационной прочности сварных соединений из двух пластин 1 и 2 прямоугольной формы и равной длины. Ширина 6 образцов составляет b = (3-5)с1_я, где - диаметр сварной точки 3. Пластины накладывают друг на друга, совмещая их по всему периметру. Обе пластины соединяют контактной сваркой. На конце каждой из пластин 1 и 2 выполняют отверстие 4, центр которого лежит на оси симметрии пластины. На оси симметрии, но на противоположном конце пластины располагают сварную точку 3. Расстояние между центрами сварной точки 3 и отверстием определяют из соотношения 1 ф (3-5)d₉· Величину усилия нагружения Р и расстояние £ выбирают в соответствии с условиями нагружения образца.A sample is welded to determine the static and vibrational strength of welded joints from two plates 1 and 2 of rectangular shape and of equal length. The width of 6 samples is b = (3-5) c1 _I, wherein - the diameter of the nugget 3. The plates are superposed on each other, combining them all around. Both plates are connected by contact welding. At the end of each of the plates 1 and 2, a hole 4 is made, the center of which lies on the axis of symmetry of the plate. A weld point 3 is located on the axis of symmetry, but at the opposite end of the plate. The distance between the centers of the weld point 3 and the hole is determined from the relation 1 f (3-5) d ₉ · The magnitude of the loading force P and the distance выбира are chosen in accordance with the loading conditions of the sample.

Для проведения испытаний образец закрепляют в нагружающем устройстве 5. Для этого валы би 7 устройства 5 пропускают через отверстие 4 образца. Последний имеет возможность свободного поворота на валах 6 и 7. Такое закрепление образца позволяет наряду с деформациями среза в точке реализовать и деформацию скручивания. Кроме того, образец и нагружающее устройство могут быть использованы для проведения вибрационных испытаний на стандартном оборудовании.For testing, the sample is fixed in the loading device 5. For this, the shafts bi 7 of the device 5 are passed through the hole 4 of the sample. The latter has the possibility of free rotation on the shafts 6 and 7. This fixing of the sample allows along with shear deformations at the point to realize twisting deformation. In addition, the sample and the loading device can be used to conduct vibration tests on standard equipment.

В зависимости от расстояния £ и усилия Р достигается одно из следующих соотношений: 7_КР= 1-сг ; г-Т_Ср или , где l_k(4 - напряжение скручивания; Т_СР - напряжение среза.Depending on the distance и and the force P, one of the following relations is achieved: 7 _KP = 1-cr; g-T _Ср or, where l _{k (4} - torsion stress; Т _СР - shear stress.

468 2468 2

Величина ширины пластины b = 3-5 задается исходя из необходимости исключить влияние граничных условий на характер образования поля остаточных напряжений сварного соединения. Из этого же условия выбирают и место расположения сварной точки относительно кромок пластины. Соотношение Е >, (3-5)d обеспечивает расположение отверстий в той части образца, которая практически свободна от остаточных технологических напряжений.The value of the plate width b = 3-5 is set based on the need to exclude the influence of boundary conditions on the nature of the formation of the field of residual stresses of the welded joint. From the same conditions, the location of the weld point relative to the edges of the plate is also chosen. The ratio E>, (3-5) d provides the location of the holes in that part of the sample, which is practically free from residual process stresses.

Таким образом и геометрические размеры образца и расположение отверстий на пластинах исключают искажение полей остаточных напряжений, возникающих при сварке, а значит повышают достоверность результатов испытаний и создают возможность проведения статических вибрационных испытаний образца.Thus, the geometric dimensions of the sample and the location of the holes on the plates exclude distortion of the fields of residual stresses that occur during welding, and therefore increase the reliability of the test results and create the possibility of static vibration testing of the sample.

Пример. Проведены испытания образца для определения статической и вибрационной прочности сварных соединений. Образцы изготавливают из ст.З, толщиной 6+6 мм. Испытывались серии образцов по 10 образцов в каждой.Example. Samples were tested to determine the static and vibrational strength of welded joints. Samples are made from st.Z, 6 + 6 mm thick. A series of samples of 10 samples each were tested.

Результаты испытаний приведены в таблице.The test results are shown in the table.

Claims

The invention relates to the field of testing the strength properties of materials and joints, and specifically to methods for determining the static and vibration strength of welded joints working on shear and twisting, especially under the conditions of prevailing shear stresses, for example, for fishing machinery. The aim of the invention is the expansion of technological capabilities by providing a complex state in a weld point. FIG. 1 shows the test scheme; in fig. 2 - fixing the sample in the fixtures. The method is carried out as follows. A sample is welded to determine the static and vibration strength of welded joints of two plates 1 and 2 of rectangular shape and equal length. The width b of the specimens is b (3-5) d, where the diameter of the welded point is 3. The plates overlap each other, aligning them all the way around. Both plates are welded together. At the end of the array of plates 1 and 2, an opening 4 is made, the center of which lies on the axis of symmetry of the plate. A weld point 3 is located on the axis of symmetry, but at the opposite end of the plate. The distance between the centers of the weld point 3 and the hole is determined from the ratio 1 - (3-5) d. The magnitude of the loading force P and the distance f are chosen in accordance with the conditions of loading the sample. For testing, the sample is fixed in the loading device 5. For this, the shafts 6 and 7 of the device 5 are passed through the opening 4 of the sample. The latter has the opportunity. free rotation on shafts 6 and 7. Such fastening of the specimen, along with shear deformations at a point, also allows twisting deformation. In addition, the specimen and loading device can be used to carry out vibration tests on standard equipment. Depending on the distance and the force P, one of the following relations is achieved: LKP -cc T., or T.r, where t is the twisting ratio; L, - strains Fr. R e 3 a. 682 The width of the plate b 3-5 is determined on the basis of the need to exclude the influence of the boundary conditions on the nature of the formation of the residual stresses of the welded joint. From the same condition, the location of the weld point relative to the edges of the plate is chosen. The ratio (3-5) d provides the location of the holes in the part of the sample that is practically free from residual process stresses. Thus, both the geometrical dimensions of the sample and the location of the holes on the plates exclude distortion of the fields of residual stresses arising during welding, and therefore increase the reliability of the test results and create the possibility of conducting static vibration tests of the sample. Example. Samples were tested to determine the static and vibration strength of welded joints. Samples are made of Art. G, 6 + 6 mm thick. Tested a series of samples of 10 samples each. The test results are shown in the table. DETAILED DESCRIPTION A method for testing static and vibration strength spot welded joints, in which two plates are welded to each other by spot welding, a load is applied to the ends of the plates and the specimen is brought to fracture, characterized in that in order to expand the technological capabilities by providing a highly stressed state nor in the welded point, the plates are made of a width equal to 3-5 diameters of the welded point, impose them on each other, combining them around the perimeter, the weld point is placed on about the bottom end of the assembled plates, and the load begins to be applied to the free ends of the plates in the direction normal to the longitudinal axis of the plates at a distance from the axis of the weld point greater than or equal to 3-5 times the diameter of the weld point and does not change sample.