SEGREGATION IN SMALL STEEL CASTINGS

Abstract

Carbon segregation in small castings often occurs near riser necks. Systematic studies were continued to determine effect on segregation of such interrelated factors as size and shape of riser and casting, and design of riser contact. Results from numerous specimens show quantitatively that intensity of carbon segregation under 'neck-down' risers varies directly as the neck length and inversely as the neck diameter. The degree of segregation also increases as the section thickness of the casting increases. Segregation beneath 'knock-off' riser contacts is minimized by (1) larger neck diameters, (2) shorter necks, (3) use of exothermic materials for 'knock-off' riser cores, (4) increase in ratio of riser thickness to casting thickness, or (5) any combination of these. Centerline segregation, resembling that in ingots, was found in long, slender castings, but this segregation relates more to centerline shrinkage than to riser contact design. Centerline segregation is reduced by increasing the taper of castings to provide more complete feeding.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Nov 22, 1948
Accession Number
AD0620569

Entities

People

  • H. F. Bishop

Organizations

  • United States Naval Research Laboratory

Tags

DTIC Thesaurus Topics

  • Base Metal
  • Castings
  • Diameters
  • Hardness
  • Heat Energy
  • Materials
  • Measurement
  • Mechanical Properties
  • Metals
  • Military Research
  • Photographs
  • Specialty Uses Of Chemicals
  • Temperature Gradients
  • Thickness
  • Transition Temperature

Fields of Study

  • Materials science

Readers

  • Metallurgy