{"id":20583,"date":"2021-06-17T07:57:20","date_gmt":"2021-06-17T07:57:20","guid":{"rendered":"https:\/\/www.meetyoucarbide.com\/?p=20583"},"modified":"2021-06-17T08:28:20","modified_gmt":"2021-06-17T08:28:20","slug":"what-is-residual-force","status":"publish","type":"post","link":"https:\/\/www.meetyoucarbide.com\/pt\/o-que-e-forca-residual\/","title":{"rendered":"O que \u00e9 For\u00e7a Residual?"},"content":{"rendered":"
\n

Em primeiro lugar, existe uma defini\u00e7\u00e3o oficial: tens\u00e3o residual \u00e9 que a pe\u00e7a de trabalho ser\u00e1 afetada por v\u00e1rios fatores de processo no processo de fabrica\u00e7\u00e3o; Quando esses fatores desaparecem, se os efeitos e influ\u00eancias acima no componente n\u00e3o podem desaparecer completamente, e alguns deles permanecem no componente, ent\u00e3o o efeito residual e a influ\u00eancia s\u00e3o tens\u00f5es residuais.<\/p>\n\n\n\n

A little dizzy? Let’s talk about it in a popular way. For example, a person was very thin before and bought a pair of L-size jeans. However, after a year, he became very fat. When he wore these jeans again, he would feel that his trousers were too tight because he was fat and his trousers didn’t change. At this time, there was a strong force between his body and his trousers. If he used too much force, it was easy to tear them, This destructive force is the effect of residual stress. From the perspective of energy work, when the external force causes the plastic deformation of the object, it will cause the internal deformation of the object, thus accumulating part of the energy; When the external force is eliminated, the energy with uneven internal stress distribution will be released. If the brittleness of the object is low, it will deform slowly, and if the brittleness is high, it will form cracks.<\/p>\n\n\n\n

A tens\u00e3o residual \u00e9 muito comum na fabrica\u00e7\u00e3o mec\u00e2nica e geralmente ocorre em todos os processos. No entanto, em ess\u00eancia, as causas do estresse residual podem ser divididas em tr\u00eas categorias<\/p>\n\n\n\n

O primeiro tipo \u00e9 a deforma\u00e7\u00e3o pl\u00e1stica n\u00e3o uniforme;<\/p>\n\n\n\n

O segundo tipo \u00e9 a mudan\u00e7a de temperatura desigual;<\/p>\n\n\n\n

O terceiro tipo \u00e9 a transi\u00e7\u00e3o de fase n\u00e3o homog\u00eanea.<\/p>\n\n\n\n

O dano do estresse residual pode ser visto a partir da classifica\u00e7\u00e3o do estresse residual. A tens\u00e3o residual pode causar a deforma\u00e7\u00e3o lenta do objeto, levar \u00e0 mudan\u00e7a do tamanho do objeto, levar ao tamanho n\u00e3o qualificado da pe\u00e7a usinada, levar \u00e0 perda de precis\u00e3o de todo o instrumento e tornar-se uma sucata na produ\u00e7\u00e3o do instrumento, e as pe\u00e7as de fundi\u00e7\u00e3o e forjamento apresentam trincas ou mesmo fraturas. Ao mesmo tempo, a resist\u00eancia \u00e0 fadiga, resist\u00eancia \u00e0 corros\u00e3o sob tens\u00e3o, as propriedades mec\u00e2nicas de todo o instrumento s\u00e3o analisadas A estabilidade dimensional e a vida \u00fatil tamb\u00e9m t\u00eam um impacto muito importante.<\/p>\n\n\n\n

Durante o processo de resfriamento, o estresse t\u00e9rmico residual \u00e9 produzido devido ao resfriamento desigual causado pelo processo n\u00e3o razo\u00e1vel, o que leva \u00e0 fratura da pe\u00e7a fundida<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Fig. 1 fratura da fundi\u00e7\u00e3o durante o resfriamento<\/p>\n\n\n\n

Durante o processo de t\u00eampera de tratamento t\u00e9rmico, a transforma\u00e7\u00e3o martens\u00edtica da austenita subresfriada \u00e9 f\u00e1cil de causar fratura do material<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Fig. 2 fratura de metal durante a t\u00eampera<\/p>\n\n\n\n

Medi\u00e7\u00e3o da tens\u00e3o residual A medi\u00e7\u00e3o da tens\u00e3o residual pode ser dividida em m\u00e9todo mec\u00e2nico, m\u00e9todo qu\u00edmico e m\u00e9todo de raios-X.<\/p>\n\n\n\n

M\u00e9todo mec\u00e2nico<\/h2>\n\n\n\n

O m\u00e9todo mec\u00e2nico mais comum \u00e9 o m\u00e9todo de perfura\u00e7\u00e3o (tamb\u00e9m conhecido como m\u00e9todo de furo cego). Em opera\u00e7\u00e3o, uma se\u00e7\u00e3o de barra (ou tubo) cujo comprimento \u00e9 tr\u00eas vezes seu di\u00e2metro \u00e9 cortada do objeto e um furo passante \u00e9 perfurado no centro. Em seguida, uma fina camada de metal \u00e9 removida de dentro pela haste ou broca, e cerca de 5% da \u00e1rea da se\u00e7\u00e3o transversal \u00e9 removida a cada vez. Ap\u00f3s a remo\u00e7\u00e3o, o alongamento do comprimento da amostra e o alongamento do di\u00e2metro s\u00e3o medidos.<\/p>\n\n\n\n

A curva de rela\u00e7\u00e3o entre esses valores e a \u00e1rea da se\u00e7\u00e3o do po\u00e7o \u00e9 desenhada, e a derivada de qualquer ponto na curva \u00e9 obtida pelo m\u00e9todo de desenho para caracterizar a taxa de varia\u00e7\u00e3o do alongamento e da se\u00e7\u00e3o do po\u00e7o, e ent\u00e3o o valor da tens\u00e3o residual pode ser obtido substituindo o f\u00f3rmula de tens\u00e3o correspondente.<\/p>\n\n\n\n

M\u00e9todo qu\u00edmico<\/h2>\n\n\n\n

Existem duas id\u00e9ias de lei qu\u00edmica. Uma ideia \u00e9 invadir a amostra em uma solu\u00e7\u00e3o adequada, medir o tempo desde o in\u00edcio da corros\u00e3o at\u00e9 a descoberta de trincas e julgar a tens\u00e3o residual de acordo com o tempo. A solu\u00e7\u00e3o utilizada pode ser merc\u00fario e sais contendo merc\u00fario para bronze de estanho e \u00e1lcali fraco e nitrato para a\u00e7o; Outra ideia \u00e9 mergulhar a amostra em uma solu\u00e7\u00e3o adequada e pes\u00e1-la em intervalos. Desta forma, podemos obter uma curva de rela\u00e7\u00e3o entre redu\u00e7\u00e3o de peso e tempo, e compar\u00e1-la com a curva padr\u00e3o para determinar o tamanho do estresse residual. Quanto maior a posi\u00e7\u00e3o da curva obtida em rela\u00e7\u00e3o \u00e0 curva padr\u00e3o, maior a tens\u00e3o residual no objeto.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Figura 3 Imers\u00e3o do metal a ser testado por m\u00e9todo qu\u00edmico<\/p>\n\n\n\n

O m\u00e9todo de raios X pode usar raios X para penetrar em pe\u00e7as met\u00e1licas, e o m\u00e9todo Laue pode determinar qualitativamente a tens\u00e3o residual interferindo na mudan\u00e7a da forma do ponto.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Figura 4 Princ\u00edpio do m\u00e9todo de raios-X<\/p>\n\n\n\n

When there is no residual stress, the interference spots are distributed as dots. When there is residual stress, the interference spots elongate and show “Star” shape.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

(a) N\u00e3o h\u00e1 tens\u00e3o residual\uff08 b) Existe tens\u00e3o residual<\/p>\n\n\n\n

Figura 5 Resultados de medi\u00e7\u00e3o do m\u00e9todo Laue<\/p>\n\n\n\n

O m\u00e9todo de Debye pode medir quantitativamente a tens\u00e3o residual, que pode ser determinada de acordo com a posi\u00e7\u00e3o, largura e intensidade da linha de difra\u00e7\u00e3o no diagrama de Debye.<\/p>\n\n\n\n

To sum up, mechanical method and chemical method are destructive testing methods, which require local sampling of the object to be tested, and the damage is irreversible after testing; X-ray method is a non-destructive testing method, which can maintain the integrity of the object. Mechanical method can accurately determine the size and distribution of residual stress, which is generally suitable for bar or tube shaped objects; Chemical method is suitable for objects of wire and sheet type, but chemical method can only make qualitative judgment, it is difficult to achieve quantitative description; Although X-ray method is a “non-destructive” method, it is only suitable for some materials that can give clear and sharp diffraction lines, and because of the small projection ability of X-ray, it can only detect the part of the object close to the surface.<\/p>\n\n\n\n

A elimina\u00e7\u00e3o do estresse residual, uma vez que existem tantos riscos de estresse residual, o m\u00e9todo de elimina\u00e7\u00e3o eficaz \u00e9 muito necess\u00e1rio. Existem quatro m\u00e9todos de elimina\u00e7\u00e3o: tratamento t\u00e9rmico, pressuriza\u00e7\u00e3o de carga est\u00e1tica, envelhecimento por vibra\u00e7\u00e3o e tratamento mec\u00e2nico.<\/p>\n\n\n\n

Tratamento t\u00e9rmico<\/h2>\n\n\n\n

O tratamento t\u00e9rmico \u00e9 usar o efeito de relaxamento t\u00e9rmico do estresse residual para eliminar ou reduzir o estresse residual. Geralmente, recozimento e t\u00eampera s\u00e3o usados.<\/p>\n\n\n\n

Static load pressurization is to adjust the residual stress of workpiece by plastic deformation of whole or part or even micro area. For example, large pressure vessels, after welding, are pressurized inside, which is called “bulging”, so that the welding joint has a small amount of plastic deformation, so as to reduce the welding residual stress.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Figura 6 Grande tanque de \u00f3leo ap\u00f3s tratamento de abaulamento<\/p>\n\n\n\n

VSR \u00e9 chamado de al\u00edvio de estresse de vibra\u00e7\u00e3o em ingl\u00eas. Al\u00edvio de tens\u00e3o vibrat\u00f3ria (VSR) \u00e9 um m\u00e9todo comum para eliminar a tens\u00e3o residual interna de materiais de engenharia. Atrav\u00e9s da vibra\u00e7\u00e3o, quando a soma vetorial da tens\u00e3o residual interna e a tens\u00e3o de vibra\u00e7\u00e3o adicional da pe\u00e7a excede a resist\u00eancia ao escoamento do material, ocorre uma pequena deforma\u00e7\u00e3o pl\u00e1stica no material, de modo que a tens\u00e3o interna do material pode ser relaxada e reduzido.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Figura 7 sistema VSR quantific\u00e1vel de tens\u00e3o<\/p>\n\n\n\n

O tratamento mec\u00e2nico \u00e9 reduzir a tens\u00e3o residual usando o m\u00e9todo de pequena deforma\u00e7\u00e3o pl\u00e1stica na superf\u00edcie do objeto, incluindo pe\u00e7as que colidem umas com as outras, lamina\u00e7\u00e3o de superf\u00edcie, desenho de superf\u00edcie e dimensionamento de superf\u00edcie e prensagem fina no molde. Por exemplo, uma das vantagens de passar a ferro \u00e9 a elimina\u00e7\u00e3o do estresse residual.<\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"

First of all, there is an official definition: residual stress is that the workpiece will be affected by various process factors in the manufacturing process; When these factors disappear, if the above effects and influences on the component can not disappear completely, and some of them remain in the component, then the residual effect and…<\/p>","protected":false},"author":2,"featured_media":20588,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[79],"tags":[],"jetpack_featured_media_url":"https:\/\/www.meetyoucarbide.com\/wp-content\/uploads\/2021\/06\/\u56fe\u724710.png","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.meetyoucarbide.com\/pt\/wp-json\/wp\/v2\/posts\/20583"}],"collection":[{"href":"https:\/\/www.meetyoucarbide.com\/pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.meetyoucarbide.com\/pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.meetyoucarbide.com\/pt\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.meetyoucarbide.com\/pt\/wp-json\/wp\/v2\/comments?post=20583"}],"version-history":[{"count":0,"href":"https:\/\/www.meetyoucarbide.com\/pt\/wp-json\/wp\/v2\/posts\/20583\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.meetyoucarbide.com\/pt\/wp-json\/wp\/v2\/media\/20588"}],"wp:attachment":[{"href":"https:\/\/www.meetyoucarbide.com\/pt\/wp-json\/wp\/v2\/media?parent=20583"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.meetyoucarbide.com\/pt\/wp-json\/wp\/v2\/categories?post=20583"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.meetyoucarbide.com\/pt\/wp-json\/wp\/v2\/tags?post=20583"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}