9CR18 steel can be processed into pipes

The 9cr18 steel on the market is generally a bar, and theoretically it can be processed into pipes.

1CR18Ni9Ti is not recommended for use in China and has been gradually eliminated.

The early researchers of stainless steel found that carbon was the main cause of the corrosion and damage of austenitic stainless steel grain boundaries, limited to the level of metallurgical equipment at that time, it was difficult to control the carbon to the following, and finally came up with the addition of Ti and Nb to the steel, so that it preferentially reacted with carbon, generated Tic and NBC, and fixed the carbon to prevent carbon from precipitating at the grain boundary to form Cr23C6, causing intergranular corrosion. Due to the high cost of NB, Ti-stabilized steel 1Cr18Ni9Ti was still dominant in stainless steels until the mid-seventies.

1Cr18Ni9Ti molten steel is viscous, and the surface quality of continuous casting billet is difficult to pass. Using die casting, the surface quality of the steel ingot is not good, and it must be peeled and regrinded, and the yield rate is very low. The finished steel contains TIN inclusions, low purity, poor surface polishing performance, and many broken wires.

By the end of the 60s of the 20th century, a breakthrough was made in stainless steel smelting technology, and AOD and VOD methods were widely used in steelmaking, and reducing the carbon in stainless steel was no longer a problem, so 1Cr18Ni9Ti was gradually replaced by low-carbon and ultra-low-carbon steel. In the seventies, the United States, Japan and other countries have eliminated 1Cr18Ni9Ti from the standard, although 0Cr19Ni11Ti (321) is retained, its output only accounts for the total, and the transition from titanium-containing stabilized steel to low-carbon and ultra-low-carbon steel has been successfully completed.

The production and application of stainless steel in China is relatively lagging behind, although in 1984 when the national standard GB1220-84 "stainless steel rod" was promulgated, 1Cr18Ni9Ti was listed as an unrecommended grade, but the dominance of 1Cr18Ni9Ti has not changed. Until 1995, with the development of the national economy, especially the intervention of joint ventures, the domestic market and the international market gradually converged, in just 5 or 6 years, China's austenitic stainless steel has completed the transition from titanium-containing stabilized steel to low-carbon and ultra-low-carbon steel. At present, except for a few traditional industries that still use 1Cr18Ni9Ti, 304 (0Cr19Ni9) and 316 (0Cr17Ni12Mo) have become the leading grades of stainless steel.

There is no such thing!

The national standard for stainless steel seamless steel pipes is "Stainless Steel Seamless Steel Pipes for Conveying Fluids" GB T14976-1994 (instead of GB2270-80). Its common specifications are shown in the following table:

<> it should be noted that 1Cr18Ni9Ti is a stainless steel product in China, and there are no completely similar alternative materials in other countries, see the table below:

<><1Cr18Ni9Ti is used in the field of chemical, coal, and petroleum industries with high requirements for grain boundary corrosiveness, and heat-resistant parts for building materials and parts with difficult heat treatment, such as:

1 .Petroleum exhaust gas combustion pipelines.

2 .Engine exhaust pipe.

3 .Boiler housings, heat exchangers, furnace components.

4 .Silencing parts for diesel engines.

5 .Boiler pressure vessels.

6 .Chemical transport trucks.

7 .Expansion joints.

8 .Spiral welded pipes for furnace pipes and dryers.

Chemical Composition Carbon C : Silicon Si: . Manganese mn: . Sulfur s : phosphorus p : chromium cr:. Nickel ni:.

Titanium ti: 5(. Mechanical properties.

Tensile Strength b (MPa): 520

Conditional yield strength (mpa): 205

Elongation δ5 (%40

Cross-sectional shrinkage 50

Hardness : 187HB; ≤90hrb;≤200hv

Heat treatment specifications and metallographic structure.

Heat treatment specifications: 1) Solid solution 920 1150 fast cooling; 2) According to the requirements of the buyer, the stabilization treatment can be carried out, and the heat treatment temperature is 850 930, but it must be specified in the contract. 3) The solution temperature should not exceed 1066, and if it does, it must be stabilized to prevent the precipitation of chromium.

Metallographic structure: The structure is characterized by austenite type.

Delivery status: generally delivered in a heat treatment state, and the type of heat treatment is indicated in the contract; If not indicated, it will be delivered in a non-heat-treated state.

The national standard for 1CR18Ni9TI stainless steel seamless steel pipe is "Stainless Steel Seamless Steel Pipe for Conveying Fluids" GB T14976-1994

1Cr18Ni9Ti is mainly used for making acid-resistant containers and equipment linings, anti-magnetic instruments, medical devices, and has good intergranular corrosion resistance.

The chemical composition of 1Cr18Ni9Ti is shown in the following figure:

Carbon C:

Silicon si:.

Manganese mn: .

Sulfur s:

Phosphorus p:

Chromium cr:.

Nickel ni:.

Titanium ti:5*(c%).

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0Cr18Ni9 is the largest and most widely used stainless steel grade, its output accounts for more than 30% of the output of stainless steel, used in the manufacture of deep-drawn molded parts, acid pipelines, storage tanks and acid storage vessels, etc., can also be used as chromium-nickel stainless steel and chromium stainless steel welding rod total materials, non-magnetic and low-temperature environment components and acid pipes, containers, etc.