304 stainless steel is a common stainless steel material, with a density of 7.93 g/cm³; It is also known in the industry as 18/8 stainless steel, which means it contains 18% or more chromium and 8% or more nickel; High-temperature resistance of 800℃, with good processing performance, high toughness, widely used in industry and furniture decoration industry and food and medical industry. But it should be noted that food-grade 304 stainless steel compared with ordinary 304 stainless steel, its content index is more strict. For example: basically, the international definition of 304 stainless steel is mainly containing chromium 18%-20% nickel 8%-10%, but food grade 304 stainless steel is containing chromium 18% and nickel 8%, allowing a certain range of fluctuations, and limiting the content of various heavy metals. In other words, 304 stainless steel is not necessarily food-grade 304 stainless steel.

Mechanical properties of 304

Tensile strength σ B (MPa)≥515-1035

Conditional yield strength σ0.2 (MPa)≥205

Elongation δ5 (%)≥40

Hardness: 201 HBW or less; 92 HRB or less; 210 hv or less

Density (20℃, g/cm³) : 7.93

Melting point (℃) : 1398~1454

Specific heat capacity (0~100℃, KJ·kg-1K-1) : 0.50

Thermal conductivity (W·m-1· k-1) :(100℃) 16.3, (500℃) 21.5

Linear expansion coefficient (10-6· k-1) :(0~100℃) 17.2, (0~500℃) 18.4

Resistivity (20℃, 10-6 ω ·m2/m) : 0.73

Longitudinal elastic modulus (20℃, KN/mm2) : 193

Application of 304 stainless steel

System description: 304 stainless steel is one of the most widely used chromium-nickel stainless steel, as a widely used steel, has good corrosion resistance, heat resistance, low-temperature strength, and mechanical properties; Stamping, bending and other thermal processing, no heat treatment hardening phenomenon (use temperature -196℃ ~ 800℃). Corrosion resistance in the atmosphere, if it is an industrial atmosphere or heavily polluted area, it needs to be cleaned in time to avoid corrosion. Suitable for food processing, storage, and transportation. It has good machinability and weldability. Plate heat exchanger, corrugated pipe, household articles (1, 2 class tableware, cabinet, indoor pipeline, water heater, boiler, bathtub), auto parts (windshield wipers, mufflers, mold products), medical appliances, building materials, chemistry, food industry, agriculture, ship parts, etc. The content of the strict control of 304 stainless steel, can also be called food grade 304 stainless steel.

Most use requirements are to preserve the original appearance of the building for a long time. When determining the type of stainless steel to choose, the main consideration is the required aesthetic standards, the location of the corrosive atmosphere and the cleaning system to be used. However, other applications increasingly seek only structural integrity or impermeability. For example, roofs and side walls of industrial buildings. In these applications, the owner's construction cost may be more important than aesthetics, and the surface may not be very clean. 304 stainless steel works well in a dry indoor environment. However, in rural and urban areas to maintain their appearance outdoors, they need to be cleaned frequently. In heavily polluted industrial and coastal areas, the surface can be very dirty and even rust.

However, in order to achieve an aesthetic effect in an outdoor environment, it is necessary to use nickel stainless steel. Therefore, 304 stainless steel is widely used in curtain walls, side walls, roofs, and other building purposes, but in the serious erosion of the industrial or Marine atmosphere, it is best to use 316 stainless steel. Stainless steel sliding door, people already realized the superiority that using stainless steel in structural applications adequately. Several design criteria include 304 and 316 stainless steel. Because "duplex" stainless steel 2205 combines excellent atmospheric corrosion resistance with high tensile strength and elastic limit strength, it is included in the European standard. In fact, stainless steel is manufactured in all standard metal shapes and sizes, and there are many special shapes as well. The most common products are made of sheet and strip steel, and special products are also made of medium-thick plates, for example, hot-rolled structural sections and extruded structural sections. There are also round, oval, square, rectangular, and hexagonal welded or seamless steel tubes and other forms of products, including sections, bars, wires, and castings.