BWG18 - BWG12 Seamless Stainless Steel Tubing ASME SA268 For Expansion Joints

Stainless Steel 440 is a ferritic, straight chromium, non-hardenable evaluation, joining great consumption resistance and form ability qualities with valuable mechanical properties. Its capacity to oppose nitric corrosive assault allows its utilization in particular compound applications yet car trim and apparatus segments speaks to its biggest fields of use.

Grade 440F is the free-machining variant of this evaluation, accessible in bar structure for utilization in programmed screw machines. Grade 434 is the molybdenum bearing rendition of Grade 440 and has the same valuable blend of properties. Its molybdenum expansion enhances consumption resistance. Stainless Steelproperties for 430 are determined for level moved item (plate, sheet and curl) in ASTM A240/A240M. Comparable yet not so much indistinguishable properties are determined for different items, for example, forgings and bar in their separate determinations. Properties of Grade 430F are indicated for bar in ASTM A582.

Applications

• Aerospace – piston engine manifolds
• Chemical Processing
• Expansion Joints
• Food Processing – equipment and storage
• Petroleum Refining – polythionic acid service
• Waste Treatment – thermal oxidizers

Typical applications for 440 grade include:

• Linings for dish washers
• Refrigerator cabinet panels
• Automotive trim
• Lashing Wire
• Element Supports
• Stove trim rings
• Fasteners
• Chimney Liners

Heat Treatment

• Solution Annealing – Heat to 815-845°C, hold for ½ hour per 25mm of thickness, slow furnace cool to 600°C and then quickly air cool. Slow cooling from 540-400°C will cause embrittlement.
• Sub-Critical anneal – Heat to 760-815°C and then air cool or water quench.
• This grade is not hardenable by thermal treatment.

Welding

• Pre-heat at 150-200°C if welding is necessary.
• Embrittlement in the weld metal and heat affected zone can be relieved by a post-weld anneal at 790-815°C
• Grain refinement will not occur.

Machining

• Easier to machine than the standard austenitic grades such as 304.
• Still a tendency for galling and pick-up on the cutting tool.
• Bars that have been lightly drawn are easier to machine than those in the annealed condition.
• Grade 430F, the free machining version of 430, is very much easier to machine.

Fabrication

• Lower work hardening rate makes bending and forming somewhat easier than for grade 304
• Lower ductility restricts very severe operations.
• Severe bends should be made with the bend axis at right angles to the rolling direction.
• Severe cold heading of 430 wire is possible.