Riser Feeding Distance (Steel Plate or Bar)
How far a single top riser feeds a steel plate or bar before centerline shrinkage forms.
Example
You enter
- Section thickness T (in) 2
- Section width W, the larger cross dimension (in) 8
- Furthest point from the riser edge (in, 0 to skip) 12
- Mold sand furan
- End chill, or a drag chill between risers end_effect
- Steel grade aisi_1025
- Pouring superheat above liquidus (F, 54 to 450) 108
You get
- Fd over t base 6.67778
- Fd (in) 13.3556
Checked against published worked examples from: Carlson, Ou and Beckermann (Steel Founders' Society of America).
Details, formula, and sources
ScopeFrom the Niyama-based rule Carlson, Ou and Beckermann published for the Steel Founders' Society in 2003. The feeding distance over the thickness follows the section's width-to-thickness ratio, then scales for the mold sand, an end or drag chill, the steel grade and the pouring superheat. A 2 by 8 in section of 1025 steel in furan sand at 108 F superheat feeds 13.36 in from the riser's edge, so a point 12 in away is sound by the rule; an end chill stretches that by 19 percent. The distance runs from the riser EDGE, the rule is fitted to sections 1 to 12 in thick, and the riser itself must still pass the modulus and volume checks.
Formula or tableend-effect feeding distance of a single top riser: FD/T = -4.29e-4 (W/T)^4 + 0.0174 (W/T)^3 - 0.266 (W/T)^2 + 1.99 (W/T) + 1.97 for W/T up to 15, and 9.0 beyond, measured from the riser edge; FD = T x (FD/T) x C_superheat x C_alloy x C_sand x C_cooling.
Source and editionCarlson, Ou and Beckermann, Feeding and Risering of High Alloy Steel Castings, Proceedings of the 57th SFSA Technical and Operating Conference, Paper 4.5 (2003), Eq. (1), Eq. (2) and Table 2, building on the carbon and low-alloy rules of Carlson, Ou, Hardin and Beckermann, Metall. Mater. Trans. B 33B (2002).
Free accessThe paper is posted by the University of Iowa Solidification Lab (beckermann.lab.uiowa.edu).
What governsEstimate. AHJ and licensed professional govern.
API field namessection_thickness_in, section_width_in, feeding_length_in, sand_mold, cooling, alloy, superheat_f, fd_over_t_base, fd_in
- Lateral feeding to W/T 15 LFD/T = -8.587e-5 (W/T)^4 + 3.408e-3 (W/T)^3 - 0.0533 (W/T)^2 + 0.6967 (W/T) + 1.019 between two top risersOu, Carlson, Hardin and Beckermann, MMTB 33B (2002), Eq. A4
- Riser assumed adequate size it on modulus and volume firstthe riser-modulus calculator
- Thin sections gated through the riser feed farther not credited; below 1 in the rule is an extrapolationthe paper, section 3