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Stainless steel round bars

Stainless steel round bars

Time:2022-04-07 Source:Wuxi Jianuo Special Steel Co.

Stainless steel round steel belongs to the category of long steel, but also belongs to the category of bars, the so-called stainless steel round steel refers to the cross-section of the uniformly round long material, generally about four meters long. It can be divided into light round and black bar. The so-called light round, refers to the smooth surface, after quasi-rolling treatment; and the so-called black bar, refers to the surface of the black thick, direct hot-rolled and come.

Introduction

Stainless steel round bar is a long solid steel with a circular cross section. Its specifications are expressed in millimeters of diameter, such as ” 50 ” that is, the diameter of 50 mm stainless steel round steel.

Common materials are 301, 304, 303, 316, 316L, 304L, 321, 2520, 201, 202, etc.. Specifications are expressed in terms of diameter, such as “50” that is, the diameter of 50 mm round steel. Round steel is divided into hot-rolled, forged and cold-drawn three. The specification of hot rolled round steel is 5.5-250mm.

Stainless Steel Round Steel

Stainless steel round steel has wide application prospects and is widely used in hardware and kitchenware, shipbuilding, petrochemical, machinery, medicine, food, electric power, energy, aerospace, etc., construction and decoration. Equipment used in sea water, chemical, dye, paper, oxalic acid, fertilizer and other production equipment; photography, food industry, coastal area facilities, ropes, CD rods, bolts, nuts .

Type characteristics

Stainless steel round steel can be divided into hot rolled, forged and cold drawn according to the production process. The specifications of hot rolled stainless steel round steel are 5.5-250 mm. Among them: 5.5-25 mm of small stainless steel round steel mostly supplied in bundles of straight bars, commonly used as reinforcing bars, bolts and various mechanical parts; greater than 25 mm of stainless steel round steel, mainly used in the manufacture of mechanical parts or for seamless steel pipe billets.

By material

1.310S stainless steel round steel

Characteristics: 310S stainless steel is austenitic chromium-nickel stainless steel has good oxidation resistance, corrosion resistance, because of the higher percentage of chromium and nickel, 310S has much better creep strength, can continue to work at high temperatures, has good high temperature resistance.

2.316L stainless steel round bar

Characteristics.

(1) cold rolled products with good glossy and beautiful appearance.

(2) due to the addition of Mo, corrosion resistance, especially excellent pitting resistance.

(3) excellent high-temperature strength;

4) excellent work hardening (weak magnetic properties after processing)

(5) solid solution state non-magnetic.

3.316 stainless steel round steel

Characteristics: 316 stainless steel is the second most widely used steel grade after 304, mainly used in the food industry and surgical equipment, because of the addition of Mo, so its corrosion resistance, atmospheric corrosion resistance and high temperature strength is particularly good, can be used in harsh conditions; excellent work hardening (non-magnetic).

4.321 stainless steel round steel

Characteristics: Ti element is added to 304 steel to prevent grain boundary corrosion, suitable for use at 430℃-900℃ temperature. In addition to the addition of titanium elements to reduce the risk of corrosion of the material weld other properties similar to 304

5.304L stainless steel round steel

Performance: 304L stainless steel round steel 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 precipitation of carbide in the heat affected zone close to the weld, which can lead to intergranular corrosion (weld erosion) of stainless steel in some environments.

6.304 stainless steel round steel

Characteristics: 304 stainless steel is the most widely used a chromium-nickel stainless steel, with good corrosion resistance, heat resistance, low temperature strength and mechanical properties. Corrosion resistance in the atmosphere, if it is an industrial atmosphere or heavily polluted areas, it needs to be cleaned in time to avoid corrosion [1] .

Corrosion Editorial Podcast

Dust particles adhering to the surface can promote corrosion of stainless steel. When dust particles are present on the surface, a gap is formed at the dust particle deposit, which tends to maintain a water film containing chloride ions and hinders the replenishment of oxygen, resulting in the destruction of the passivation film. In addition, this dissolution zone and the passivation zone near the dust particle deposition will form an occlusion cell exacerbates the formation and development of pitting pits.

Oxidation treatment

(1) Sandblasting (shot) method: mainly using the method of spraying micro glass beads to remove the black oxide skin on the surface.

(2) Chemical method: the use of a non-polluting pickling passivation paste and room temperature non-toxic cleaning solution with inorganic additives for dipping and washing. Thus achieving the purpose of whitening treatment of stainless steel natural color. After the treatment basically looks like nothing light color. This method is more applicable to large and complex products.

Implementation standards

Stainless steel round national standard: GB/T1220-2007.

American Standard: ASTM A484/A484M, ASTM A213/213A , ASTM A269/269M.

Surface treatment: industrial surface, brushed surface, bright surface, re-polishable.

Cost calculation: round steel price * [1-(10-discount rate)/10] + rolling fee + polishing fee + sizing fee + packaging + transportation.

Distinction

In construction projects, stainless steel round bars and rebar is the common name for different kinds of steel bars, the differences between them are mainly the following five points.

1. Different appearance. The outer surface of stainless steel round bars is smooth; the outer surface of rebar has a spiral rib.

2. Production standards are different. In the current standard, stainless steel round bar refers to HPB235 grade reinforcement, its production standard is “hot-rolled smooth reinforcement for reinforced concrete” (GB13013); rebar generally refers to HRB335 and HRB400 grade reinforcement, its production standard is “hot-rolled ribbed reinforcement for reinforced concrete” (GB1499).

3. The strength is different. The design strength of stainless steel round bar (HPB235) is 210MPa; the strength of rebar is higher than that of stainless steel round bar, the design strength of HRB335 is 300MPa; the design strength of HRB400 is 360MPa.

4. Different steel grades, (different chemical composition). Stainless steel round bar (HPB235) is carbon steel, steel grade is Q235; rebar is low alloy steel, HRB335 grade steel is 20MnSi (20 manganese silicon); HRB400 grade steel is 20MnSiV or 20MnSiNb or 20MnTi, etc..

5. Different physical and mechanical properties. Due to the different chemical composition and strength of the steel bars, they are different in physical and mechanical properties. Stainless steel round steel cold bending performance is better, you can make 180 degrees of bending hook, rebar can only make 90 degrees of straight hook; stainless steel round steel weldability is better, with ordinary carbon welding rod can be, rebar must use low-alloy welding rod; rebar in toughness, fatigue resistance than stainless steel round steel. Rebar is generally used in the construction of reinforced concrete facilities, the material is generally low-alloy steel grade is generally 16Mn (16 manganese low-alloy steel), or 45 carbon steel, their yield strength are more than 350Mpa, tensile strength are in 500Mpa up and down, than ordinary low carbon steel stainless steel round steel is much higher (after heat treatment of the strength of the rebar can be low carbon stainless steel round steel nearly One time or more). Because the surface has a threaded shape, can increase the solid bond with the concrete. Concrete members with longitudinal reinforcement, hoop reinforcement, etc. should be preferred to use rebar.

In summary, because the rebar is a low-alloy steel, its price is higher than low-carbon stainless steel round, the contractor, or design units, often to the general civil construction of the “practicality” point of view, reduce the quality of engineering positioning, and the choice of low-carbon stainless steel round instead of rebar. For large key projects, often appear to buy “after the project inspector”, stainless steel round steel to replace the ribbed steel “to pump the beam for the column” to reduce construction costs, in the design, because the members are not allowed to hoop to provide “main stress support”, the main role is to “maintain the shape and position of the longitudinal tendons”, stainless steel round steel has a smooth surface, binding positioning accurate, so, in addition to the longitudinal tendons, permission to use round do steel hoops . And longitudinal bars must always use ribbed steel .