Stainless Simbi 321 Strip ine Yakanakisa Weldability yekudziya Element Tubing

● Grades 321 and 347 are the basic austenitic 18/8 steel (Grade 304) stabilized by Titanium (321) or Niobium (347) additions. These grades are used because they are not sensitive to intergranular corrosion after heating within the carbide precipitation range of 425-850 °C. Grade 321 is the grade of choice for applications in the temperature range of up to about 900 °C, combining high strength, resistance to scaling and phase stability with resistance to subsequent aqueous corrosion.
Grade 321H is a modification of 321 with higher carbon content, to provide improved high-temperature strength.

● A limitation with 321 is that titanium does not transfer well across a high-temperature arc, so it is not recommended as a welding consumable. In this case grade 347 is preferred - the niobium performs the same carbide stabilization task but can be transferred across a welding arc. Grade 347 is, therefore, the standard consumable for welding 321. Grade 347 is only occasionally used as parent plate material.

● Like other austenitic grades, 321 and 347 have excellent forming and welding characteristics, are readily brake or roll-formed and have outstanding welding characteristics. Post-weld annealing is not required. They also have excellent toughness, even down to cryogenic temperatures. Grade 321 does not polish well, so is not recommended for decorative applications.

● Grade 304L is more readily available in most product forms, and so is generally used in preference to 321 if the requirement is simply for resistance to intergranular corrosion after welding. However, 304L has lower hot strength than 321 and so is not the best choice if the requirement is resistance to an operating environment over about 500 °C.

Key Properties
● These properties are specified for the flat-rolled products (plate, sheet, and coil) in ASTM A240/A240M. Similar but not necessarily identical properties are specified for other products such as pipe and bar in their respective specifications.

Kurwisana Kurwisana
● Yakaenzana neGiredhi 304 mune yakavharwa mamiriro, uye yepamusoro kana weldment mumagiredhi aya isati yaitwa post-weld annealed kana kana application ichisanganisira sevhisi mu425-900 °C renji. Zvichienderana negomba uye kukoromoka kwevhu munzvimbo dzinodziya dzechloride, uye kusimbisa ngura inotsemuka pamusoro pe60 °C. Inofungidzirwa kuti inoshingirira kumvura inonwiwa inosvika 200 mg/L chlorides pane tembiricha yakapoteredza, ichidzika kusvika pa150 mg/L pa60 °C.

Kupisa Kupisa
● Kuramba kwakanaka kweoxidation musevhisi yepakati kusvika ku900 °C uye musevhisi inoenderera kusvika 925 °C. Magiredhi aya anoita zvakanaka muchikamu che425-900 ° C, uye kunyanya apo panowanikwa aqueous corrosive conditions. 321H ine yakanyanya kupisa simba uye inonyanya kukodzera kune yakakwirira-tembiricha zvimiro zvekushandisa.

Kurapa kwekupisa
● Kugadzirisa Kurapa (Annealing) - kupisa kusvika 950-1120 ° C uye kutonhora nokukurumidza nokuda kwekudzivirira kukuru kwekuora.
● Kudzikamisa - kupisa kusvika ku870-900 ° C kweawa imwe pa1mm yehukobvu uye mhepo inotonhorera. Kudzikamisa kunokurudzirwa kune yakanyanya kuomarara sevhisi mamiriro (pamusoro pe25 ° C) uye kunyanya kune zvinhu zvakavharirwa padivi rekumusoro kweiyo annealing tembiricha.
● Kubvisa Kushungurudzika - Kupisa kusvika ku700 °C kwemaawa 1 kusvika ku2 uye mweya unotonhorera.
● These grades cannot be hardened by thermal treatment.

Welding
● Excellent weldability by all standard fusion methods, both with and without filler metals. AS 1554.6 pre-qualifies welding of 321 and 347 with Grade 347 rods or electrodes; a high silicon version of 347 is also pre-qualified for welding of 321.

Mechanical Properties
Yakajairika mechanicha zvivakwa zvegiredhi 321 Stainless sheets esimbi inopihwa mutafura 2.

Proper Properties
Zvakajairwa zvimiro zveannealed giredhi 321 Stainless sheets esimbi anopihwa mutafura 3.

Giredhi Specification Kuenzanisa
Approximate grade comparisons for 321 stainless sheets of steel are given in table 4.

Possible Alternative Grades
Possible alternative grades to grade 321 stainless sheets of steel are given in table 5.

● Aircraft exhaust manifolds
● Expansion joints
● Mvura
● Furnace parts
● Heating element tubing
● Heat Exchangers
● Woven or welded screens for high-temperature mineral processing
● Spiral Welded tube for burner pipes and flues