{"id":734,"date":"2026-05-21T09:36:45","date_gmt":"2026-05-21T09:36:45","guid":{"rendered":"https:\/\/www.wudejiansteel.com\/?p=734"},"modified":"2026-05-21T09:36:46","modified_gmt":"2026-05-21T09:36:46","slug":"the-mandrels-used-for-punching-round-tubes-are-prone-to-breaking-so-lg-tool-steel-which-can-withstand-being-bent-without-breaking-must-be-used-blog-129","status":"publish","type":"post","link":"https:\/\/www.wudejiansteel.com\/?p=734","title":{"rendered":"The mandrels used for punching round tubes are prone to breaking, so LG tool steel\u2014which can withstand being bent without breaking\u2014must be used.blog\u00a0129"},"content":{"rendered":"\n

\u00a0A Douyin user messaged me asking: \u201cI\u2019ve used DC53, CALDIE, and SKH55 for the mandrel in round tube punching. After producing about 5,000 pieces, it broke. What tool steel<\/a> <\/strong>should I use?\u201d<\/p>\n\n\n\n

This type of mandrel is used for punching tubular parts. It extends into the tube but is used as a cutting edge, with one end suspended in the air. Since the mandrel is small and involves drilling, there is very little material to support the edge. This leads to insufficient strength: low-hardness steel will suffer from corner collapse and dull cutting edges, while high-hardness steel is prone to breaking. For this application, you should select a die steel with high hardness and good toughness.<\/p>\n\n\n\n

The user is currently using DC53, CALDIE, and SKH55, all of which are prone to breaking. They break after just 5,000 pieces. This is because the mold steel used is too brittle, and the material selection is incorrect.<\/p>\n\n\n\n

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\u00a0Of these three materials, SKH55 is likely the one that breaks most easily. It is a high-speed steel<\/a><\/strong>\u00a0containing 5.5% cobalt with a hardness of 63\u201364HRC. While it offers excellent wear resistance, it is very brittle, so it\u2019s normal for it to break easily. The next most prone to breaking is DC53, a high-carbon steel\u00a0with a carbon content of 1.0%. A common drawback of high-carbon steel is its poor toughness. The same applies to CALDIE: although it performs better than DC53, it is still too brittle. The fact that it breaks after just 5,000 stamping cycles further confirms this.<\/p>\n\n\n\n

For this type of single-sided cantilevered bridge-type mandrel fracture, I recommend the high-toughness LG die steel<\/a><\/strong>.<\/p>\n\n\n\n

LG is a proprietary high-toughness die stee<\/strong>l developed by Yuhui Company. LG\u2019s toughness is 8 to 9 times that of DC53, with a hardness of 54\u201358HRC. It is so tough that it will not break even if bent by hand.<\/p>\n\n\n\n

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 Mr. Chen, who manufactures stamped pipe fittings, had been using single-arm cantilever mandrels made of Cr12MoV, SKD11, and DC53. However, all of them broke after just a few hundred to a thousand pieces, making production unfeasible due to excessive mandrel wear, high costs, and low efficiency.<\/p>\n\n\n\n

But after switching to Yuhui\u2019s high-toughness LG die steel<\/strong>, the mandrels remained intact even after stamping over 30,000 pieces. The mandrel lifespan has increased from a few hundred to a thousand cycles to 30,000 cycles\u2014a 30-fold improvement.<\/p>\n\n\n\n

This user has used DC53, CALDIE, and SKH55 for round tube punching mandrels, but they all broke after producing around 5,000 pieces. I recommend you use high-toughness LG tool steel<\/strong>.<\/p>\n\n\n\n

Using LG tool steel<\/strong> for mold cracking is like stepping into a liberated zone.<\/p>\n\n\n\n

*************<\/p>\n\n\n\n

Wu Dejian’s <\/strong>tool<\/strong> steel<\/strong>, the chief of staff of the user, bought everything he had used.<\/p>\n","protected":false},"excerpt":{"rendered":"

\u00a0A Douyin user messaged me asking: \u201cI\u2019ve used DC53, CALDIE, and SKH55 for the mandrel in round tube punching. After producing about 5,000 pieces, it broke. What tool steel should I use?\u201d This type of mandrel is used for punching tubular parts. It extends into the tube but is used as a cutting edge, with […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-734","post","type-post","status-publish","format-standard","hentry","category-blog"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t