{"product_id":"carbon-steel-square-tubing-4in-x-3-16in-x-36in-structural-grade","title":"Carbon Steel Square Tubing 4in x 3\/16in x 36in - Structural Grade","description":"\u003cp\u003eOur review looks at the OnlineMetals A500\/A513 carbon steel square tubing and finds it best suited for builders and fabricators who need a straightforward, structural-grade stick of steel. The bottom line: this 4 in square tube with a 3\/16 in wall and 36 in length delivers solid rigidity and easy modification, making it a practical choice for machine supports, frames, and hobbyist metalwork where a durable, recyclable material is required.\u003c\/p\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHigh-strength carbon steel:\u003c\/strong\u003e Provides dependable structural integrity for frames, supports, and load-bearing assemblies.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e4 in height, 3\/16 in wall:\u003c\/strong\u003e The wall thickness balances weight and stiffness for common fabrication tasks without excessive bulk.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e36 in length:\u003c\/strong\u003e A ready-to-use 3 ft section that fits many workshop projects and reduces cutting time for common layouts.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUncoated and modifiable:\u003c\/strong\u003e Ships raw so it can be welded, drilled, cut, or otherwise altered to match design requirements.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurable and recyclable:\u003c\/strong\u003e Engineered to resist wear with long service life while remaining recyclable at end of use.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMultipurpose utility:\u003c\/strong\u003e Works with standard tube connectors and fittings for machine fab, model builds, and separator systems.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWho It's For\u003c\/h2\u003e\n\u003cp\u003eThis tubing is aimed at tradespeople, engineers, and serious hobbyists who need a dependable, structural steel section for load-bearing or fabricated parts. Its 3\/16 in wall and 4 in profile suit small to medium frames, jigs, and machine supports where stiffness and the ability to weld or bolt are key.\u003c\/p\u003e\n\u003cp\u003eThose who prioritize a ready-to-finish surface for painting or decorative use should plan for surface treatment after purchase, and anyone requiring stainless-grade corrosion resistance or precision-ground surfaces for aesthetics should consider alternative materials designed specifically for those needs.\u003c\/p\u003e\n\u003ch2\u003ePros \u0026amp; Cons\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePros\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eGood structural strength for frames and supports given the 3\/16 in wall thickness.\u003c\/li\u003e\n\u003cli\u003eReady for modification: welds, drills, and cuts cleanly for custom projects.\u003c\/li\u003e\n\u003cli\u003ePractical 36 in length fits many shop layouts and reduces waste from oversize stock.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eCons\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eUncoated finish can show surface rust in some environments, so exterior use may need protection.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003ctable\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaterial\u003c\/td\u003e\n\u003ctd\u003eCarbon steel (A500\/A513), ASTM A-36\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eShape\u003c\/td\u003e\n\u003ctd\u003eSquare tubing\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHeight\u003c\/td\u003e\n\u003ctd\u003e4 in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWall thickness\u003c\/td\u003e\n\u003ctd\u003e3\/16 in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLength\u003c\/td\u003e\n\u003ctd\u003e36 in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFinish\u003c\/td\u003e\n\u003ctd\u003eHot rolled, uncoated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch2\u003eOur Verdict\u003c\/h2\u003e\n\u003cp\u003eThe OnlineMetals carbon steel square tubing is a solid, no-nonsense choice for fabricators who need a 4 in by 3\/16 in structural member in a 36 in length. It offers flexibility for welding and machining, sensible durability, and good value for functional projects; just plan on surface protection if corrosion resistance is important for your application.\u003c\/p\u003e\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eCan this tubing be welded?\u003c\/strong\u003e\u003cbr\u003eYes. The hot-rolled carbon steel is suitable for common welding processes and can be welded for structural joints.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it come coated to prevent rust?\u003c\/strong\u003e\u003cbr\u003eNo. It is supplied uncoated, so exterior or wet-environment use should include a rust-prevention finish or paint.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs the length exact 36 in?\u003c\/strong\u003e\u003cbr\u003eYes. The product is sold as a 36 in stick, which is convenient for many shop applications and reduces initial cutting.\u003c\/p\u003e","brand":"Online Metals","offers":[{"title":"Default Title","offer_id":48240454729947,"sku":"B000H9KE1Y","price":98.49,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/51mvzNj-mjL._AC_SL1000_2a3c6155-b56e-4e2f-ac03-add7769d59ba.jpg?v=1771087540","url":"https:\/\/gearmusthave.com\/products\/carbon-steel-square-tubing-4in-x-3-16in-x-36in-structural-grade","provider":"GearMustHave","version":"1.0","type":"link"}