304L is a versatile stainless steel, which is widely used in the manufacture of equipment and parts requiring good comprehensive properties (corrosion resistance and formability).
Chemical composition
Name :304L stainless steel plate, 304L stainless steel plate, 304L stainless steel 8K plate
Brand :00Cr19Ni10(0Cr18Ni10)
Chemical composition %
P :≤0.035
S :≤0.03
Cr :18.0 to 20.0
Ni :8.0~10.0
Mechanical property
Yield strength (N/mm2)≥205
Tensile strength ≥520
Elongation (%)≥40
Hardness HB ≤187 HRB≤90 HV ≤200
Density 7.93 g·cm-3
Specific heat c(20℃)0.502 J·(g·C)-1
Thermal conductivity λ/W(m·℃)-1 (at the following temperatures /℃)
20 100 500
12.1 16.3 21.4
Linear expansion coefficient α/(10-6/℃) (between the following temperatures /℃)
20 to 100 20 to 200 20 to 300 20 to 400
16.0 16.8 17.5 18.1
Resistivity 0.73 Ω·mm2·m-1
Melting point 1398~1420℃
Defect class
Classification number Typical defect Common defect
Raw material defects 28 Metal ball marks, marbling, longitudinal cracks and scratches, foreign body compression, contamination, creasing, poor winding
Cold rolling defects 30 roll marks, roll surface roughness, roll vibration marks, crow's feet, fine wrinkles, wave defects, pad paper pressing
Annealing Pickling 32 Over pickling, annealing pickling, under pickling, under annealing, pitting, rust, brush roll marks, rubber residue, white spots, pickling liquid residue, stop in the furnace
Finishing defects 30 poor degreasing, uneven grinding, striations, rough edges
Numbering of steel
① Use the international chemical element symbol and the national symbol to indicate the chemical composition, and use the Arabic alphabet to indicate the component content: such as: China, Russia 12CrNi3A
② Use fixed digit numbers to represent steel series or numbers; Such as: United States, Japan, 300 systems, 400 systems, 200 systems; ③ Use the Latin alphabet and order to form the serial number, only to indicate the purpose.
Labeling method
The American Iron and Steel Institute uses three digits to label various standard grades of malleable stainless steel. Among them: ① Austenitic stainless steel is indicated by 200 and 300 series numbers, ② ferrite and martensitic stainless steel is indicated by 400 series numbers. For example, some of the more common austenitic stainless steels are marked with 201, 304L, 316 and 310, ③ ferritic stainless steels are marked with 430 and 446, martensitic stainless steels are marked with 410, 420 and 440C, and are biphase (austenitic-ferrite). Stainless steel, precipitation-hardened stainless steel and high alloys with an iron content of less than 50% are usually patented or trademarked names.
distinction
Now the two most commonly used stainless steel 304,316 (or corresponding to the German/European standard 1.4308,1.4408), 316 and 304 in the chemical composition of the main difference is that 316 contains Mo, and it is generally recognized that 316 corrosion resistance is better than 304 in high temperature environment more corrosion resistance. Therefore, in a high temperature environment, engineers generally choose parts of 316 material. But the so-called thing is not absolute, in the concentrated sulfuric acid environment, then high temperature do not use 316! Or this is gonna be a big deal. Mechanical people have learned thread, remember in order to prevent thread bite at high temperatures, need to apply a black solid lubricant: molybdenum disulfide (MoS2), from which it draws 2 conclusions is not :[1]Mo is indeed a high-temperature material (know what crucible gold melts with? Molybdenum crucible!) . [2] Molybdenum readily reacts with high sulfur ions to form sulfide. So no stainless steel is super resistant to corrosion. In the end, stainless steel is a piece of impurities (but these impurities can be more corrosion resistant than steel ^^) more steel, steel can react with other substances.
use
Properties and uses of stainless steel
As a low-C 304 steel, in the general state, its corrosion resistance is similar to 304 steel, but after welding or stress, its grain boundary corrosion resistance is excellent. In the case of no heat treatment, it can also maintain good corrosion resistance, generally used below 400 (non-magnetic, use temperature -196 degrees Celsius to 800 degrees Celsius).
It is used in chemical, coal and petroleum industries with high grain boundary corrosion resistance, internal and external open-air machines, building materials, heat-resistant parts and parts with difficulty in heat treatment.
The development of 304L stainless steel has made the corrosion resistance, appearance, processability, strength and other characteristics of 304L stainless steel far more than other materials, and many surface treatment methods of stainless steel can obtain colorful colors and shapes, which makes a great contribution to the development of stainless steel.
304L stainless steel manufacturing process surface treatment method and mechanical grinding surface treatment method
Summary use of surface feature manufacturing method
NO.1 A rough, matte surface hot rolled to a specified thickness and then annealed and descaled, which does not require a surface gloss
NO.2D silver white cold rolling after heat treatment and pickling, sometimes in the rough surface roller for the final light rolling a matt surface processing 2D products for the surface requirements are not strict use, general materials, deep drawing materials
NO.2B luster stronger than NO.2D NO.2D treatment, through the polishing roller for a final mild cold rolling, to obtain the appropriate luster. This is the most commonly used surface finish, which can also be used as the first step in polishing. General timber
BA is as bright as a mirror without standard, but it is usually a bright annealed surface processing, and the surface reflectivity is very high. Building materials, kitchen utensils
NO.3 Rough grinding will be NO.2D and NO.2B wood, with 100~200#(unit) strop grinding belt, grinding construction materials, kitchen utensils
NO.4 Intermediate grinding NO.2D and NO.2B materials are polished by grinding with a 150 to 180# strop grinding strip, which is a universal, specular reflecting bright surface with visible 'grains'
NO.240 Fine grinding NO.2D and NO.2B wood are ground with a 240# strop strip for kitchen utensils
NO.320 Ultra-Fine grinding Grind NO.2D and NO.2B materials with a 320# strop grinding strip
NO.400 gloss is close to BA NO.2B material, grinding with 400# polishing wheel general materials, building materials, kitchen utensils
HL hairline grinding suitable particle size grinding material for hairline grinding (150~240#) its strop many buildings, building materials
NO.7 Close to mirror grinding with 600# rotary polishing wheel grinding art, decoration
NO.8 Mirror grinding mirror polishing wheel grinding mirror, decorative
301 stainless steel shows obvious work hardening phenomenon during deformation, and is used in various occasions requiring higher strength.
302 stainless steel is essentially a variant of 304 stainless steel with higher carbon content, which can be obtained with higher strength through cold rolling.
302B is a kind of stainless steel with high silicon content, which has high resistance to high temperature oxidation.
303 and 303Se are free-cutting stainless steels containing sulfur and selenium, respectively, for applications where the main requirements are easy cutting and high surface finish. 303Se stainless steel is also used to make parts that require hot upsetting, because under these conditions, this stainless steel has good hot workability.
304L is a variant of 304 stainless steel with a lower carbon content and is used in applications where welding is required. The lower carbon content minimizes the carbides precipitated in the heat-affected zone near the weld, which can lead to intergranular corrosion (welding erosion) in stainless steel in some environments.
304N is a nitrogen-containing stainless steel, and nitrogen is added to improve the strength of the steel.
305 and 384 stainless steels contain high nickel, and their work hardening rate is low, which is suitable for various occasions with high requirements for cold formability.
308 stainless steel is used to make welding rods.
The nickel and chromium content of 309, 310, 314 and 330 stainless steels is relatively high, in order to improve the oxidation resistance and creep strength of the steel at high temperatures. The 30S5 and 310S are variants of 309 and 310 stainless steel, the difference is that the carbon content is lower, in order to minimize the carbide precipitated near the weld. 330 stainless steel has particularly high carburization resistance and thermal shock resistance.
Type 316 and 317 stainless steels contain molybdenum, so the resistance to point corrosion in Marine and chemical industry environments is much better than 304 stainless steels. Among them, type 316 stainless steel consists of variants including low-carbon stainless steel 316L and nitrogen-containing high-strength stainless steel.
316N and high sulfur content of free cutting stainless steel 316F.
321, 347 and 348 are titanium, niobium plus tantalum, niobium stabilized stainless steel, suitable for use at high temperature welding components. 348 is a stainless steel suitable for the nuclear power industry, which has a certain limit on the amount of tantalum and drill.
Weight formula Weight (kg)= thickness (mm)* Width (m)* Length (m)* density value
