APPLICATION
These ranges of steel grades are intended for structural work where no significant forming or bending has to be done.The steel grade selected should be in accordance with its strength requirements as indicated in Table 3. 

STEEL GRADES
The following steel grades to SABS 1431:1987 are produced.

-    Grade 240 WA        240 WC        240 WDD*
-    Grade 300 WA        300 WC        300 WDD*
-    Grade 350 WA        350 WC        350 WDD*
* Available only as plate mill products.

As can be seen from Table 3, the mechanical strength properties are the same throughout a grade range but the impact test requirements differ according to the prescribed test temperatures as indicated by the suffix per grade designation.  An average impact energy value of 27 J must be achieved on full size specimens in the longitudinal direction in all applicable cases.

STEELMAKING
Steel for all grades to SABS 1431 is normally made as silicon killed steel and is also aluminium treated as standard practice to ensure a fine grain structure. The supply conditions pertaining to each steel grade are shown in Table 1.

PLATE AND SHEET
Sheet applies for products less than 4.5 mm  thick, whereas plate refers to products of 4.5 mm and thicker.  Different dimensional tolerances apply to sheet and plate.

Products up to and including 13 mm thick and up to and including 1850 mm wide (when side trimmed) are normally produced on a hot strip mill.

CHEMICAL COMPOSITION
Table 1 gives the values as specified in Table 2 of SABS 1431, 1987 (as amended).  The limits are set very wide offering the steelmaker maximum scope to apply his manufacturing techniques to obtain the specified mechanical properties in the final products.

When agreed at the time of ordering, plates of SABS 1431 steel grades can be supplied to the following maximum carbon equivalent (CE) values:

240WA,    WC & WDD    =    0.38%
300WA,    WC & WDD    =    0.45%
350WA,    WC & WDD    =    0.43%

TABLE 1 - Chemical composition % (ladle analysis) as specified in SABS 1431, 1987 
- Table 2 (as amended) 

1. Plates may be ordered with 0.20 / 0.35% copper for improved atmospheric corrosion resistance.
2. Trace elements only.
3. Can be supplied controlled rolled.
    

TABLE 2    -    Typical chemical composition 

1. C usually is 0.02% lower on all hot strip mill products.

2. Mn Usually is 0.30% lower on all hot strip mill products.

3. For applications where toughness or through thickness strength is important, the plates may be ordered as per appendix A of  SABS 1431 to the following stricter sulphur contents : - Clause 0.11:S = 0.025% max - Clause 0.12:S = 0.012% max - Clause   0.13:S = 0.005% max

4. Substantially lower Si contents may be used.

WELDABILITY
The SABS 1431 range of structural steel grades is readily weldable by means of the usual metal-arc processes.  When welding thick plates, reference should be made to BS 5135:1984 "Specification for arc welding of carbon manganese steels"  Carbon equivalent (CE) values should be calculated from the values of the chemical composition indicated on the test certificates for the plates concerned.  The formula to be used is:

CE = C + Mn + Cu + Ni + Mo + V + Cr
                   6            5                  15
 

ULTRASONIC TESTING
Plates may be ordered ultrasonically tested to any grade of BS 5996, as outlined in SABS 1431 Appendix B-2:014 (16 - 80mm)
 
 
BEND TEST
If agreed at the time of ordering, the material may be subjected to a bend test as detailed in SABS 1431 paragraph 6.5.5.

CERTIFICATION
All plates are supplied with analysis and test certificates.

TOLERANCES
Plate are supplied with dimensional tolerances according to BS EN 10051:1992
 

TABLE 3 - Mechanical properties as specified in SABS 1431 - 1987:  Table 5