diamond<\/em> (10), which is the hardest naturally occurring stone.<\/p>\nHardness<\/h3>\n
Since shot is used to peen inherently hard materials such as hardened steels (with high surface hardness) and pre-hardened steels (with a surface hardness of about 500-600 HV), it needs to be very hard<\/strong> and wear-resistant<\/strong> itself.<\/p>\nAs explained before in the section on shot peening machines, shot is fired, hits the surface, falls to the bottom of the machine, is recovered, and its size is checked with a sieve before being reintroduced into circulation. If the shot falls below a certain size, it is discarded. A hard shot can withstand a certain number of impacts<\/strong> and be used multiple times before being discarded. However, with each impact, the shot undergoes a deformation that reduces its size and often causes it to break.<\/p>\nTypical hardness values are:<\/p>\n
Steel<\/em>: 600-700 HV<\/p>\nGlass\/Ceramic<\/em>: 700 to 1,000 HV, and for specific applications, up to 1,250 HV<\/p>\nCorundum<\/em>: 600 to 800 HV<\/p>\nParameters that Define Shot Peening:<\/h2>\n
This section is crucial for the know-how of each company. Therefore, we will not go into detail on the contents.<\/p>\n
As mentioned, the effects of shot peening on springs can only be measured by estimating residual stresses, and thus with X-ray diffraction<\/strong>.<\/p>\nThe measurement of the energy action of shot peening is empirically done with the Almen<\/em> system, which estimates the potential of the shot peening machine.<\/p>\nThe other parameters that vary from spring to spring are the batch size to be peened (charge quantity) and the cycle time.<\/p>\n
Based on the performance of their own shot peening system, each spring manufacturer establishes their own shot peening cycles.<\/p>\n
At Mollificio Valli<\/strong>, the combination of these parameters, supported by verification with microscopy and fatigue testing on peened and unpeened springs, allows us to guarantee the fatigue performance of the springs and the maintenance of such performance over time, in various batches.<\/p>\nThe overall knowledge<\/strong> gained over the years and the use of high-resolution<\/strong> digital investigation tools contribute to the development of a concrete methodology<\/strong> in defining shot peening cycles and controls.<\/p>\nThe control of the shot peening process, like any other process, can only be achieved by defining measurable<\/strong> parameters that can be monitored in real-time or in a preventive manner.<\/p>\nAt Mollificio Valli<\/strong>, we have a quality control<\/strong> department that manages and monitors the shot peening process by performing regular checks on:<\/p>\n\n- Incoming shot checks;<\/li>\n
- Verifying shot peened springs under a microscope;<\/li>\n
- Conducting fatigue tests on shot peened and unpeened springs;<\/li>\n
- Measuring shot peening machine efficiency through periodic Almen<\/em> tests;<\/li>\n
- Monitoring parameters of eddy current devices<\/em> installed in-line on our coilers to detect and discard material sections with surface defects.<\/li>\n<\/ul>\n
If shot peening is a crucial factor<\/strong> in the fatigue resistance of the spring, for particularly demanding applications in terms of life cycles, Mollificio Valli<\/strong> is ready to collaborate with you and provide over thirty years of expertise.<\/em><\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"Shot peening is a mechanical process that has a considerable impact on the durability and performance of springs. When it comes to producing fatigue-resistant components, shot peening becomes a crucial step in the manufacturing process. In this article, we will explore the role of shot peening in spring production and how it affects their strength […]<\/p>\n","protected":false},"author":5,"featured_media":17775,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[318,332],"tags":[],"class_list":["post-17955","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news-en","category-technical-articles"],"_links":{"self":[{"href":"https:\/\/mollificiovalli.it\/en\/wp-json\/wp\/v2\/posts\/17955","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mollificiovalli.it\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mollificiovalli.it\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mollificiovalli.it\/en\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/mollificiovalli.it\/en\/wp-json\/wp\/v2\/comments?post=17955"}],"version-history":[{"count":0,"href":"https:\/\/mollificiovalli.it\/en\/wp-json\/wp\/v2\/posts\/17955\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mollificiovalli.it\/en\/wp-json\/wp\/v2\/media\/17775"}],"wp:attachment":[{"href":"https:\/\/mollificiovalli.it\/en\/wp-json\/wp\/v2\/media?parent=17955"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mollificiovalli.it\/en\/wp-json\/wp\/v2\/categories?post=17955"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mollificiovalli.it\/en\/wp-json\/wp\/v2\/tags?post=17955"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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