This page contains a Flash digital edition of a book.
Improving Casting Quality Through Sand, Metallurgy


A sampling of white paper technical presentations from the 119th Metalcasting Congress focus on sand and metal for improved cast components. A MODERN CASTING STAFF REPORT


discussions as well as white paper technical presentations that reveal the results of recent and ongoing research designed to improve the quality of metalcasting operations. We have selected three of the white papers that were presented in April to summarize below. Tese well-reviewed technical papers from leading experts in the field represent lab studies that could have a practical impact on cast component quality.


E


Presentation Comparing Sand Additives for


Steel Castings (15-006)


Authors Ralph Showman and


Eric Scheller, ASK Chemi- cals, Dublin, Ohio


Background Sand additives com-


monly are used in sand molds and cores for steel castings. Te additives can impact casting qual- ity both physically and chemically by reducing casting defects like vein- ing, metal penetration and surface finish. Chemical interactions between the steel and mold/core mate- rials like carbon pickup or dissolved gas also can be minimized. Historically, iron ox-


very year, Metalcasting Congress is anchored by a peer-reviewed technical program featuring panel


(magnetite, Fe3O4 O3


ides have been the additives of choice for steel castings. Both red iron oxide (hematite, Fe2


of 51 and 34. Te additives tested


) and black iron oxide ) have been used


successfully. However, iron oxides also can have negative impacts both in cost and casting quality. A number of en- gineered sand additives (ESAs) have been developed that are advertised to provide lower cost, improved veining resistance, or fewer gas defects, etc., but little comparative data has been available.


A design of experiments was devel- oped to compare the performance of several ESAs to red and black iron ox- ides. Two different additive levels, high and low for each type, were selected. Two sands were selected, both round grain high purity silica with AFS GFN


included: • Sand additive SX, a synthetic ESA consisting primarily of iron oxide but with a grain size similar to sand and a rounded particle shape.


• RIO, red iron oxide or hematite (Fe2


• Additive V2, a mineral ESA with some red iron oxide.


O4


• BIO, black iron oxide or magne- tite (Fe3


O3 ).


• Additive I900, a mineral ESA with some red iron oxide.


• V400, a mineral ESA based on red iron oxide.


• V2003, a mineral ESA that con- tains spodumene, a lithium ore.


• IL, a naturally occurring mineral called ilmenite. Te impact on the


mold/core properties and on casting quality was measured over a range of process parameters, including work time/strip time, tensile strength, humidity resistance, permeability and smoke opacity. Tis may provide some additional insight on which sand additive should be used to achieve a particular set of desired results.


Conclusions


The test casting with gating (left) and the casting and riser sections (right) used in the sand additives study are shown.


30 | MODERN CASTING May 2015


Te results of the design of experiments highlight the strengths and weaknesses of various sand additives and provide


).


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76