Introduction
ste500 is a code that shows up in steel catalogues, engineering datasheets and product listings, and it points first of all to a high-strength structural steel grade from Germany. The grade sits in the family of weldable fine-grain structural steels defined by the German standard DIN 17102, with forgings covered by DIN 17103, and its name carries its most useful fact in plain sight: the number 500 stands for a minimum yield strength of 500 megapascals. Anyone who orders, designs with, welds or inspects structural steel will meet this grade in bridges, pressure vessels, storage tanks and heavy machine frames.
The same code also appears on products that have nothing to do with steelmaking. A computer power supply, a sewage treatment unit, a hospital treatment unit, a punch press and an air receiver tank all carry a version of the ste500 label, and a reader who searches the term can land on any of them. This article explains what ste500 steel is, its chemistry and strength figures, where it is used, how it is welded and checked, which grades match it, and what the other ste500 products are. Readers who follow structural steel guides will find the same plain approach here: verified figures first, and anything that could not be verified marked UNCONFIRMED rather than guessed. In standards documents the grade is printed with capital letters, while this article uses the lowercase form ste500 throughout, exactly as the keyword is written.
The 500 in ste500: What the Number Means
The number in ste500 is not a model year, a size or a price. It is the grade’s minimum yield strength, measured at 500 megapascals, and that one number tells a designer most of what the grade is for. Yield strength is the stress at which steel stops springing back and starts to deform for good, so a higher yield strength means a beam, column or plate can carry a heavier load before it takes a permanent set. A megapascal equals one newton per square millimetre, and 500 is a demanding figure for a weldable structural steel, well above the 355 megapascals of the widely used S355 grade. The gap from 355 to 500 shows how much more load a ste500 section can carry than an S355 section of the same size.
The letters in front of the number carry meaning too. The grade belongs to the weldable fine-grain structural steel family, and the fine grain is the heart of the story. Fine grain means the steel’s crystal structure is made of very small grains, and small grains give steel a rare combination: high strength together with toughness at low temperature and good behaviour under welding. Ordinary structural steel gains strength mainly from carbon, but carbon makes welding harder and the steel more brittle in the cold. ste500 keeps carbon low and gains its strength from grain refinement plus small additions of manganese, vanadium and niobium.
ste500 Chemical Composition and the Limits That Define It
ste500 chemistry is defined by limits rather than by a single recipe, and the limits are what make the grade weldable. Carbon is capped at 0.21 percent, which is low for a steel of this strength, and that low ceiling is the main reason the grade welds well. Manganese runs from 1.00 to 1.70 percent and does much of the strengthening work, while silicon sits from 0.10 to 0.60 percent and acts as a deoxidiser during steelmaking. Phosphorus is held to a maximum of 0.035 percent and sulfur to a maximum of 0.030 percent, because both elements harm toughness and weld quality when they rise. These are the DIN 17103 datasheet limits, and they are the figures a mill certificate is checked against.
Small additions complete the chemistry. Nickel is allowed up to 1.00 percent, chromium up to 0.30 percent, molybdenum up to 0.10 percent and copper up to 0.20 percent. Vanadium is capped at 0.22 percent and niobium at 0.05 percent, with the sum of niobium, titanium and vanadium capped at 0.22 percent, and aluminium has a minimum of 0.02 percent because aluminium helps to pin the fine grain in place during heat treatment. Nitrogen is capped at 0.02 percent. None of these additions is present in a large amount: the grade gets its strength from a fine grain and a careful balance, not from a heavy dose of alloy.
ste500 Mechanical Properties Across Thickness and Delivery Condition
The mechanical properties of ste500 start with the yield strength of 500 megapascals minimum, which is the figure the grade is named for, and a tensile strength of 600 to 700 megapascals for plate under DIN 17102 figures. Tensile strength is the stress at which the steel finally breaks, so the gap from 500 to 600 megapascals and above is the reserve that lets a structure carry overloads and absorb shocks without failing. Elongation sits at about 16 to 20 percent, which measures how far the steel can stretch before it breaks, and that stretch is what gives a structure warning before failure instead of a sudden snap. Density is 7.84 grams per cubic centimetre, and the elastic modulus is 212 gigapascals at 20 degrees Celsius, which fixes how much a ste500 beam bends under a given load.
Those headline figures shift with thickness, form and delivery condition, and honest datasheets show a range rather than one number. Normalized ste500 data lists yield strength from 410 to 500 megapascals and tensile strength from 570 to 780 megapascals, with elongation of 16 percent, and the lower end of the yield range belongs to the thickest sections. The reason is cooling: a thick plate cools more slowly after rolling, its grain grows a little coarser, and its yield strength falls. A designer who uses ste500 must therefore check the strength figure for the actual thickness on the drawing, not the headline 500. The grade is commonly supplied normalized, marked plus N, and also quenched and tempered or annealed, in forms from plate and bar to forgings, tubes and profiles. The lowest application temperature is minus 20 degrees Celsius.
| Property | ste500 Figure |
|---|---|
| Standard | DIN 17102 (plates and sections), DIN 17103 (forgings, 1989 edition) |
| Type | Weldable fine-grain structural steel |
| Minimum yield strength | 500 MPa (headline figure; 410 to 500 MPa across the normalized thickness range) |
| Tensile strength | 600 to 700 MPa (plate); 570 to 780 MPa (normalized, thickness-dependent) |
| Elongation | About 16 to 20 percent |
| Density | 7.84 g/cm3 |
| Elastic modulus at 20 C | 212 GPa |
| Lowest application temperature | Minus 20 C |
| Material number | 1.8907 |
| European equivalent | S500N under EN 10025-3 |
| Japanese equivalent | JIS SM570 |
| Common forms | Plate, bar, forgings, tube, strip, sheet, profiles |
Where ste500 Is Used: Bridges, Pressure Vessels and Heavy Structures
ste500 is used where a structure must be strong, light and welded, and bridges are the clearest case. Bridge steel under this grade goes into riveted and bolted bridge structures such as highway bridges, railway bridges, sea bridges, overpasses, viaducts and large overhead cranes, where every tonne saved in the deck is a tonne less for the piers and foundations to carry. The grade suits bridge work because its strength lets designers use thinner plates, its toughness holds up in cold weather, and its weldability lets workshops join long girders and complex nodes. A bridge built with ste500 carries the same traffic on less steel, and the saving runs through the whole structure.
Pressure vessels and storage tanks are the second home of ste500. The grade is listed for welded constructions of many kinds, including pressure vessels, stationary and mobile storage tanks and high-pressure lines, where the steel must hold pressure from inside while staying tough enough to resist a crack. A pressure vessel wall made from ste500 can be thinner than one made from ordinary structural steel at the same pressure, which cuts weight and welding time. Construction, vehicles and heavy machinery take the rest: buildings use it for beams, columns and frames, vehicles for chassis and structural parts, and heavy machinery and shipbuilding for parts under heavy loads and repeated stress.
Welding and Fabrication: What Workshops Watch For With ste500
ste500 welds well for a steel of its strength, and the low carbon ceiling is the reason, but welding it still needs the care that any high-strength steel demands. The standard advice is to use proper preheating and post-weld heat treatment where the joint and thickness call for it, because fast cooling after welding can harden the joint area and open the way to cracking. Welders also watch heat input, since too much heat can coarsen the fine grain near the joint and take away the very property that gives the grade its strength. A workshop that treats ste500 like mild steel will run into trouble, and the cost shows up as rework or as a joint that fails its test.
Cutting and handling need the same care. Cutting methods should limit thermal distortion so that plates stay flat and parts fit together without force, and stored plate should be kept dry so that rust does not start before fabrication. Finished parts should be inspected for defects, above all after heavy loads. A delivery should arrive with an original mill test certificate under EN 10204 3.1, recording the heat, the chemical analysis and the mechanical test results. A delivery without a certificate, or with figures outside the DIN limits, should be queried before any cutting starts.
DIN 17102, DIN 17103 and the Modern Equivalent Grades
ste500 lives under two German standards that cover two forms of the same grade. DIN 17102 covers weldable fine-grain structural steels in plate and section form, and DIN 17103 covers weldable fine-grain structural steel forgings, with the 1989 edition of DIN 17103 listing the grade among its grades. The two standards share the grade name and chemistry limits; the difference is the product form. A buyer who orders plate quotes DIN 17102, a buyer who orders a forging quotes DIN 17103, and the mill certificate should name the standard that matches the form supplied.
The grade also has a material number, 1.8907, which is the fixed identifier used in steel databases and stock lists across Europe. Its European equivalent is S500N under EN 10025-3, the current European standard for normalized fine-grain structural steels, and its Japanese equivalents are JIS SM570 and JIS SM58. These equivalents are not the same steel under another name; they are grades from other standards with matching chemistry and strength, and an engineer who swaps one for another should still check the certificate figures rather than trusting the match on paper. The DIN 17102 family also has prefixed variants, with one prefix marking a weather-resistant version, one marking a low-temperature version and one marking an elevated-temperature version. That web of equivalents is useful because ste500 itself is an older German grade, and modern European projects usually specify S500N under EN 10025-3 instead. UNCONFIRMED: the exact date DIN 17102 was withdrawn, and which mills still roll ste500 today.
Other Products That Carry the ste500 Code
The best-known other ste500 is the Cougar ste500, model CGR ST-500, a 500-watt ATX power supply from the Cougar XTC series, made by Compucase Enterprise Co., Ltd. Its manual lists an AC input of 200 to 240 volts at 50 hertz, efficiency up to 83 percent, active power factor correction up to 98 percent, a 120-millimetre temperature-controlled fan, PCI Express 3.0 support through 8-pin connectors, a 20-plus-4-pin motherboard connector and 4-pin and 8-pin processor power. Retail listings give its size as 150 by 140 by 86 millimetres, its weight as 1.83 kilograms, an 80 PLUS White rating and a 12-volt output of 456 watts. It shares nothing with the steel grade except the code and the number 500. Its launch year and current availability are UNCONFIRMED, and at least one retail listing shows it as not available.
Three industrial products also use the code. The STE-500 sewage treatment unit is listed with a capacity of 500 cubic metres per day, power of 18.5 kilowatts, dimensions of 12.0 by 5.5 by 3.5 metres and a BOD removal rate of 96 percent or more. The ST-E500 is a hospital ear, nose and throat treatment unit sold by Pioway, with CE and ISO certification and a rated power of 1,600 volt-amperes maximum. The STE-500 punch press is a closed double-point crank precision press from Qiaosen, rated at 500 tonnes and built to JIS Class 1 accuracy standards. A fifth use is the STE-500 litre receiver tank, a mild steel compressed-air storage vessel sold by Snap Air Compressor of Pune, listed with a 500-litre capacity, a maximum pressure of 12 bar and a listing price of 23,000 rupees per piece. That price is a seller’s listing figure, not a verified market price, and no current price for ste500 steel per tonne or for any of these units could be verified.
How to Check a ste500 Mill Certificate Before Buying
Buying ste500 well starts with the mill certificate, and the check is short. The certificate should name the grade ste500, the standard DIN 17102 or DIN 17103 to match the form, the heat number, the chemical analysis and the mechanical test results, and it should be an original mill test certificate under EN 10204 3.1. The chemistry figures should sit inside the DIN limits given earlier in this article. The mechanical results should show a yield strength at or above the figure for the thickness ordered and a tensile strength inside the 600 to 700 megapascal range for plate. Any figure outside those limits is a reason to stop and ask.
The second check is the form and condition: the certificate must match the form delivered, and the delivery condition should be the one the design calls for. The third check is the supplier: buy from a stockist or mill that issues the EN 10204 3.1 certificate as a matter of course, and keep the certificate with the job records. Readers who want more background on engineering explainers of this kind will find the same rule repeated there: the paper that proves the steel is part of the steel. The price and the source of supply cannot be checked from a datasheet, and both are UNCONFIRMED. No current per-tonne price could be verified, and no single official ste500 website exists, since the code belongs to a standard and to several unrelated products rather than to one company.
ste500 Frequently Asked Questions
What is ste500?
ste500 is a high-strength weldable fine-grain structural steel grade under the German standard DIN 17102, with forgings under DIN 17103. It is used in bridges, pressure vessels, storage tanks, vehicles and heavy machinery, and its name records its minimum yield strength of 500 megapascals. The code is also used by unrelated products that share only the name.
What does the 500 in ste500 mean?
The 500 stands for a minimum yield strength of 500 megapascals, the stress at which the steel starts to deform permanently. A megapascal equals one newton per square millimetre. The figure is measured at the reference thickness and falls a little as plate thickness rises.
What is ste500 used for?
ste500 is used for welded constructions that need high strength at low weight, including bridges, pressure vessels, storage tanks, high-pressure lines, building frames, vehicle chassis and heavy machinery parts. Its strength lets designers use thinner sections, which cuts the weight of the whole structure.
Can ste500 be welded?
Yes. Its low carbon ceiling of 0.21 percent is the reason it welds well for a steel of its strength. Proper preheating and post-weld heat treatment should be used where the joint and thickness call for it, and heat input should be watched so that the fine grain near the joint is not coarsened.
What is the chemical composition of ste500?
The DIN 17103 limits are carbon up to 0.21 percent, manganese from 1.00 to 1.70 percent, silicon from 0.10 to 0.60 percent, phosphorus up to 0.035 percent and sulfur up to 0.030 percent, with small caps on nickel, chromium, molybdenum, copper, vanadium and niobium, and at least 0.02 percent aluminium.
What are the equivalent grades of ste500?
The material number of ste500 is 1.8907, its European equivalent is S500N under EN 10025-3, and its Japanese equivalents are JIS SM570 and JIS SM58. An engineer who swaps one for another should still check the certificate figures for the batch in hand.
Is ste500 the same as the Cougar ste500 power supply?
No, the two share only the code. The Cougar ste500, model CGR ST-500, is a 500-watt ATX computer power supply from the Cougar XTC series, made by Compucase Enterprise Co., Ltd. It has no link to the steel grade, and the same is true of the other products that carry versions of the code.
Where can ste500 be bought?
ste500 can be bought from steel suppliers and stockists who carry fine-grain structural grades, and the delivery should come with an original mill test certificate under EN 10204 3.1. The current price per tonne and the list of mills now rolling the grade are UNCONFIRMED, so a buyer should ask for a written quote naming the grade, standard, form, thickness and delivery condition.
Conclusion
ste500 is first of all a high-strength weldable fine-grain structural steel whose name states its promise, a minimum yield strength of 500 megapascals, and whose low carbon and fine grain let it carry heavy loads in bridges, pressure vessels, tanks and machines while staying weldable and tough down to minus 20 degrees Celsius. Its equivalents, S500N in Europe and SM570 in Japan, show that the material is a recognised grade, and its mill certificate is the proof that any delivery lives up to the name. The same code also labels a computer power supply and several industrial machines that share nothing with the steel except the letters and the number. A reader who checks the maker, the model and the certificate before ordering will always land on the right ste500.
