{"id":699,"date":"2024-08-16T18:08:11","date_gmt":"2024-08-16T12:38:11","guid":{"rendered":"https:\/\/www.solitaire-overseas.com\/blog\/?p=699"},"modified":"2026-06-30T17:54:01","modified_gmt":"2026-06-30T12:24:01","slug":"en8-material-composition","status":"publish","type":"post","link":"https:\/\/www.solitaire-overseas.com\/blog\/en8-material-composition\/","title":{"rendered":"EN8 Carbon Steel – Chemical Composition & Equivalents Grades"},"content":{"rendered":"
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Mild Steel<\/b>, also known as Carbon Steel, refers to low carbon steel that lacks any alloying elements and has a carbon content of up to 0.25%. The term ‘Mild’ encompasses a broad range of steel specifications and forms used in various applications.<\/span><\/p>\n

Mild Steel is commonly used in mechanical engineering for components that do not experience high levels of stress. When it undergoes bright cold drawing, the steel can withstand higher stress, especially in smaller diameters.<\/span><\/p>\n

Bright Mild Steel offers several advantages over standard mild steel, including tighter sectional tolerances, better straightness, and a cleaner surface finish. Cold drawing allows the steel to be closer to the final machining size, which helps reduce machining costs. Additionally, bright steel bars have significantly higher physical strength compared to hot rolled bars of the same size.<\/span><\/p>\n

EN8<\/b>, also known as unalloyed medium carbon steel (BS 970 080M40), has higher strength levels than typical bright mild steel due to thermo-mechanical rolling. EN8 is versatile and well-suited for various engineering purposes where greater strength is required.<\/span><\/p>\n

View Our Carbon Steel Pipes & Tubes \u2192<\/b><\/a>\u00a0<\/span><\/p>\n

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What is EN 8 Carbon Steel?<\/b><\/h3>\n

EN8 carbon steel is a medium carbon and medium tensile strength steel known for its improved strength over mild steel. It is often chosen for applications that need better durability and can be through-hardened, making it suitable for parts that undergo wear and tear. EN8 is also appreciated for its good machinability in various conditions, making it versatile for different engineering uses.<\/span><\/p>\n

While EN8 steel is typically used in its untreated state, it can be surface-hardened through induction processes, enhancing its wear resistance. Heat treatment of EN8 steel leads to consistent machining properties due to its uniform metallurgical structure. For sections larger than 65mm, good results can still be achieved with heat treatment, though mechanical properties may slightly diminish towards the center of the material. Therefore, larger sizes are often supplied untreated, with heat treatment performed after initial stock removal to achieve better properties near the core.<\/span><\/p>\n

Classified under the British standard BS970 as 080M40, EN8 is also known globally by names like <\/span>C45 in the EU, 1040 steel in the USA, and S40C in Japan<\/b>. It is widely used in engineering and construction due to its reliable structural strength. Compared to bright mild steel, EN8 offers superior tensile strength, making it a cost-effective choice for applications that demand more robust performance without compromising on quality.<\/span><\/p>\n

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EN8 Steel Grade Specification<\/b><\/h3>\n\n\n\n\n\n\n\n\n\n
EN8 Steel<\/th>\nDetails<\/th>\n<\/tr>\n<\/thead>\n
Standard<\/td>\nBS 970-1955<\/td>\n<\/tr>\n
Steel Grade<\/td>\nEN8<\/td>\n<\/tr>\n
Purpose<\/td>\nWrought steel for mechanical and allied engineering applications<\/td>\n<\/tr>\n
Other Common Grades in BS 970-1955<\/td>\nEN9, EN19, EN24, EN36<\/td>\n<\/tr>\n
Equivalent Grade in BS 970-1991<\/td>\n080M40 steel<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

This table provides a concise summary of EN8 steel as specified in the BS 970-1955 standard and its equivalent in the BS 970-1991 standard.<\/p>\n

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Chemical Composition of EN8 Steel<\/b><\/h3>\n\n\n\n\n\n\n\n\n\n
Element<\/th>\nContent (%)<\/th>\n<\/tr>\n<\/thead>\n
C (Carbon)<\/td>\n0.36 \u2013 0.44<\/td>\n<\/tr>\n
Mn (Manganese)<\/td>\n0.60 \u2013 1.00<\/td>\n<\/tr>\n
Si (Silicon)<\/td>\n0.05 \u2013 0.35<\/td>\n<\/tr>\n
P (Phosphorus)<\/td>\n0.015 \u2013 0.06<\/td>\n<\/tr>\n
S (Sulphur)<\/td>\n0.015 \u2013 0.06<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

EN8 Steel Mechanical Properties<\/h3>\n\n\n\n\n\n\n\n\n
Heat Treatment<\/th>\nTensile Strength Rm (MPa)<\/th>\nYield Strength Rp0.2 (MPa)<\/th>\nA min 5.65\u221aSo<\/th>\nIzod Ft.lb<\/th>\nKCV J<\/th>\nHardness HB<\/th>\n<\/tr>\n<\/thead>\n
N<\/td>\n550<\/td>\n280<\/td>\n16<\/td>\n15<\/td>\n16<\/td>\n152\/207<\/td>\n<\/tr>\n
\u2014<\/td>\n510<\/td>\n245<\/td>\n17<\/td>\n\u2013<\/td>\n\u2013<\/td>\n146\/197<\/td>\n<\/tr>\n
Q<\/td>\n625\/775<\/td>\n385<\/td>\n16<\/td>\n25<\/td>\n28<\/td>\n179\/229<\/td>\n<\/tr>\n
R<\/td>\n700\/850<\/td>\n465<\/td>\n16<\/td>\n25<\/td>\n28<\/td>\n201\/255<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Welding EN8 Steel<\/b><\/h3>\n

Welding EN8 steel has become easier with modern EN8 bright mild steel due to its lower carbon content. For sections up to 18 mm thick, you can weld without preheating using MIG wire (SG2) or a 7018 electrode.<\/span><\/p>\n

For sections thicker than 18 mm, it’s recommended to preheat the steel to 100\u00b0C (212\u00b0F) to prevent the risk of cracking during the welding process.<\/span><\/p>\n

EN8 Carbon Steel Equivalent Grades<\/b><\/h3>\n

Here are the equivalents of EN8 carbon steel grade in various standards:<\/span><\/p>\n\n\n\n\n\n\n\n\n\n
Standard<\/th>\nEquivalent Grade(s)<\/th>\n<\/tr>\n<\/thead>\n
BS 970-1991<\/td>\n080M40<\/td>\n<\/tr>\n
AISI\/ASTM A29<\/td>\n1038, 1040, 1045<\/td>\n<\/tr>\n
DIN Werkstoff No.<\/td>\n1.0511, 1.1186, 1.1189<\/td>\n<\/tr>\n
BS & DIN European<\/td>\nC40, CK40, C45, CK45<\/td>\n<\/tr>\n
JIS G4051<\/td>\nS40C, S45C<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Heat Treatment of EN8 Carbon Steel<\/b><\/p>\n

EN8 steel is generally supplied untreated but can be ordered in normalized or heat-treated conditions for specific applications.<\/span><\/p>\n