Aviation, spaceflight and transportation industry

1.  Aviation , spaceflight industry.

1. The aviation, spaceflight industry use large sums of stainless steel to make components related with the motor, the steel types in use include martensite stainless steel, austenite stainless steel and precipitation hardening stainless steel.(1) Martensite stainless steel.
   In the spaceflight industry, the representative steel grade in use include 1Cr13/TP410、2Cr13/TP420、1Cr17Ni2、9Cr18Mo/TP440C, ect.
   1Cr13/TP410 and 1Cr17Ni2 are used to produce components with good hardness and tenacity, like the accessories of the exhaust gangway around the motor, and the storage tank for rocket fuel.2Cr13/TP420 and 9Cr18Mo/TP440C are used to make components with high hardness, like the rods, paw, pin, etc. 9Cr18Mo/TP440C is also used to make components in high temperature and periodic motion, oil pressure components, fastening pieces, etc.

   (2) Austenite stainless steel.
   In the aviation industry, the austenite stainless steel is mainly applied in large liquid fuel carrier rocket, high strength low temperature pressure vessel and low pressure fluid container, shown in the following table:

The application of austenite stainless steel in the aviation industry

(3) Precipitation hardening stainless steel.
Large quantities of precipitation hardening stainless steel are applied in the aviation industry, the brands involved including PH13-8Mo、15-5PH、17-4PH、Custom455、AM350、A-286, etc. These materials are mainly used in the mechanical system of aircraft, including bolts, gears, pothooks, rods, pipe joints, elastic elements, etc. For example, PH14-8Mo is used in the rear screen board of the Apollo satellite; 15-5PH is used in the wing joist of the large plane XB-70; A-286 is used in the fastening pieces of spacecrafts, etc.

2. Transportation industry.
(1) The rail vehicles used stainless steel.
In order to reduce weight and promote quality, the passenger compartment of the rail department, the subway compartment and city light rail compartment, ect, are all constructed with the various hardening state 1Cr17Ni7/TP301 stainless steel, and the city electric buses are also equipped with the material 0Cr18Ni5Mn9N(202).

The  TP304L is used for the decoration of railway vehicle.  TP316 can also be used for the compartment toilet to resist the corrosion of human urine.

(2) Ships
Ship structure　The ships for transporting food, chemical products, cold store, etc, will be built with  TP321 steel or 18Cr-8Ni clad plate as the material for cabin. The liquid gas transportation ships are built with the Cr-Ni austenite stainless steel that has good low temperature performance. Minesweeper, invisible submarine, etc, will be built with high strength non-magnetism austenite stainless steel as the material for the hull, like 00Cr21Ni17Mo2N and 00Cr22Ni13Mo3N, etc.

Equipments on board　The stainless steel is mainly used in the kitchen related equipments, the main brand is TP304 and 0Cr17. High strength austenite stainless steel or double phase steel is used in the periscope pipe and mast stainless steel.

Engine　The marine diesel engine and steam turbine are the main power machine of the ship. Among these, the supercharger, turbine blade, exhaust valve are all made of stainless steel.  TP316 is used in the exhaust system, and 12CrMo and 17-4PH steel are used in the turbine blades. Cr-Ni austenite stainless steel is used in the non-magnetic engine.

Propulsion system　With the increasing of the size and speed of the ships, the hardness of the propeller blade and its air corrosion resistance have become important problems concerning the present propeller material, and there is the trend that the original manganese bronze is about to be substituted by aluminum bronze.

The Cr13 marten site stainless steel has been successfully used in small size ships while  TP316、0Cr25Ni5Mo2 double phase steel and 0Cr17Ni7Al precipitation hardening stainless steel are used in large size ships to make the screw propeller, in which the inblock cast and soldering block can both be used, for the purpose of preventing sea water corrosion, and electric-chemistry protection is usually carried out.

(3) Automobile industry.
With the development of automobile industry, the application of stainless steel in the area is becoming wider and wider, and the application scope is no longer limited to decoration, but has extended to frame, exhaust system, engine components. Today, a family car will probably consume 20-30KG stainless steel, during the early 90’s of the twentieth century, Japan consumed about 100 thousand to 130 thousand tons of stainless steel in automobile industry each year.

Auto frame stainless steel　The auto frame or the complete vehicle crust of high speed bus, has been successfully made of stainless steel containing 11%-12%Cr, with the life span of at least 10-20 years. The brands include 409（00Cr11Ti）, 408（00Cr12Ti NbAl AM363(0Cr11Ni4Ti), 00Cr12NiTi, etc. The latter was widely used in large buses, coal transporting trucks, city subway compartment and various cleaning vehicles, watering vehicles and tow trucks, etc, in the countries including South Africa, Britain, Australia, Belgium, etc; sometimes,  TP304 will be applied in combination. It is estimated that Europe’s requirements to these type of steel will reach 1 million tons. The usage proves: after driving 1.2 million km, the exposed frame parts are still in a very good state, those parts with the peeling of painted cover or damages caused by colliding stones show no sign of corrosion. For the parts inside the vehicle which are without any protection, no corrosion is found, and the surface is as smooth as before.

Stainless steel used in exhaust system　Stainless steel material has been used in the auto exhaust system in substitute of aluminizing material, to guarantee the requirement of 5 years operation without repairing; from the viewpoint of being economical and practical, it is common that the 0Cr11Ti (409) type ferrite stainless steel is chosen; while there are many Japanese brands, mostly of which are based on 13Cr-17Cr ferrite stainless steel and its improved type; on some parts, the Cr-Ni austenite stainless steel is also used, the table below shows the steel application general situation in the present auto exhaust system. In the world wide scale, Europe and Americas mainly use 409 ferrite stainless steel; the annual requirements of North America is up to 400 thousand tons, while the American Nucor Company produces 400 thousand tons of cold rolling sheets on the CSP line for the usage in auto industry.

Stainless steel used in auto exhaust system

Auto components　When Auto components use stainless steel, apart from the steel’s original function, it must be decorative, thus to increase the appearance of the auto. The  TP304 and Cr17 stainless steel are commonly used in these components, shown in the following table:

Stainless steel used in auto components