Casting answers & advice.Q: We occasionally experience significant drops in casting hardness in our ductile iron Ductile iron, also called ductile cast iron or nodular cast iron, is a type of cast iron invented in 1943 by Keith Millis[1]. While most varieties of cast iron are brittle, ductile iron is much more ductile, as the name implies. pearlitic grades. Although we can not identify any changes in melt chemistry or metal processing, the problem comes and goes without warning. What are some potential reasons for a drop in hardness in ductile iron?Background: Ductile iron foundries typically produce castings to meet various industry-recognized standards, such as ASTM ASTM abbr. American Society for Testing and Materials . The grades of iron designated in these standards include different hardness specifications. In order to obtain higher hardness levels, foundries may add alloying elements such as copper, tin and manganese manganese (măng`gənēs, măn`–) [Lat.,=magnet], metallic chemical element; symbol Mn; at. no. 25; at. wt. 54.938; m.p. about 1,244°C;; b.p. about 1,962°C;; sp. gr. 7.2 to 7. . On occasion, these alloying schemes (which have historically proven to be effective), fail to produce the intended hardness to meet the requirements. To compensate for the drop in hardness, this particular foundry was increasing the alloying elements in their 80-55-06 iron to higher than usual levels (even up to levels that would normally make 100-70-03 iron), yet still were periodically unable to hit the necessary yield strength. Recommendations: Once the chemistry and shakeout Shakeout A situation in which many investors exit their positions, often at a loss, because of uncertainty or recent bad news circulating around a particular security or industry. Notes: During the dotcom boom and bust, numerous shakeouts occurred. time related issues have been ruled out as the cause of the poor hardness, the foundry might consider boron boron (bōr`ŏn) [New Gr. from borax], chemical element; symbol B; at. no. 5; at. wt. 10.81; m.p. about 2,300°C;; sublimation point about 2,550°C;; sp. gr. 2.3 at 25°C;; valence +3. contamination as a potential cause. Boron contamination can negate ne·gate tr.v. ne·gat·ed, ne·gat·ing, ne·gates 1. To make ineffective or invalid; nullify. 2. To rule out; deny. See Synonyms at deny. 3. the strengthening additions and reduce the hardness below acceptable standards. Potential sources of boron can include scrap steel, alumina alumina (əl  `mĭnə) or aluminum oxide, Al2O3, chemical compound with m.p. about 2,000°C; and sp. gr. about 4.0. or silica silica or silicon dioxide, chemical compound, SiO2. It is insoluble in water, slightly soluble in alkalies, and soluble in dilute hydrofluoric acid. Pure silica is colorless to white. lining in coreless electric
furnaces electric furnace: see furnace. electric furnace Chamber heated with electricity to very high temperatures, for melting and alloying metals and refractories. Modern electric furnaces generally are either arc furnaces or induction furnaces. , binders and fillers used in some charge materials, and possibly other sources that have yet to be discovered. Although many iron foundries do not typically test for boron and may not have a boron channel on their spectrometer spectrometer Device for detecting and analyzing wavelengths of electromagnetic radiation, commonly used for molecular spectroscopy; more broadly, any of various instruments in which an emission (as of electromagnetic radiation or particles) is spread out according to some , foundries experiencing softness issues might consider testing for boron content as part of their chemical analysis. However, accurate analysis can be difficult, even from outside labs, due to the fact that in some foundries this softening effect takes place at extremely low boron concentrations (5 to 20 ppm). An increase in boron of 5 ppm (an increase from 0.000-0.0010% boron) can reduce yield strength 4 to 5 ksi in 80-55-06 grades. There are many varieties of test equipment available, yet the spectrometer remains the most reliably accurate instrument for boron detection. Standards used for developing useful curves should have points between 3 and 100 ppm. If boron is believed to be coming from the lining of the furnace, a simple solution is not to produce pearlitic grades for the first few ladles from furnaces that have been relined or have undergone extensive patching. If boron can't be determined as coming from the furnace lining material, foundry personnel may want to check for boron levels in incoming scrap. Sheet steel manufacturers often add boron to aid formability, so some high-strength low-alloy steel from prime sheet busheling charge material also may be a source. The information submitted in this column was supplied by the AFS A distributed file system for large, widely dispersed Unix and Windows networks from Transarc Corporation, now part of IBM. It is noted for its ease of administration and expandability and stems from Carnegie-Mellon's Andrew File System. AFS - Andrew File System Cast Iron Div. Molten Metal Processing Committee (5-L). Q: What is the timeline for companies that are currently certified to QS-9000:1998 to transition to the new ISO/TS 16949:2002? Background: In order for the ISO (1) See ISO speed. (2) (International Organization for Standardization, Geneva, Switzerland, www.iso.ch) An organization that sets international standards, founded in 1946. The U.S. member body is ANSI. 9000 family of standards to maintain effectiveness, the standards are periodically reviewed to benefit from new developments in the quality management field and to incorporate user feedback. The ISO 9000 standard was recently changed and ISO 9000:2000 is the current available standard. Senior management can use the quality management system standards in the revised ISO 9000:2000 series as a framework to guide their organizations towards improved performance. Answer: The existing ISO 9000:1994 standard expires in December 2003. Companies currently certified to QS-9000:1998 can either update their system to the new ISO version, and the QS-9000 requirements, or drop the ISO 9000 certificate. Registrars will honor the QS-9000 standard until December 2006 when that standard will become obsolete. ISO/TS 16949:2002 is currently available for registration. Companies supplying Daimler Chrysler must be certified to the ISO/TS 16949:2002 standard by July 2004. This includes VDA VDA Vendor Driven Architecture VDA Verband Der Automobilindustrie E.V. (German Automobile Industry Association) VDA Virginia Department for the Aging VDA Ovda, Israel (Airport Code) VDA Visual Data Analysis 6.1 subscribers (see Automotive Industry The automotive industry is the industry involved in the design, development, manufacture, marketing, and sale of motor vehicles. In 2006, more than 69 million motor vehicles, including cars and commercial vehicles were produced worldwide. Action Group www.aiag.org). Ford and General Motors have announced that they will honor the December 2006 deadline. QS-9000 TE and semiconductor suppliers have been recommended to maintain existing certifications, but should be proactive and ready to transition to ISO/TS 16949:2002. The information in this column was supplied by the AFS Engineering Div. Quality Systems Committee (1-J). Recommendations are the opinion of the AFS Technical Dept. based on referenced literature and experience. If you need assistance with a technical issue, fax or email your question to: Casting Answers & Advice, c/o MODERN CASTING, at 847/824-7848 or moderncasting@afsinc.org.
Table 1
Quality Standards' Expected Change Dates
Quality Standard Expected Change Date
ISO 9000: 1994 Expires December 2003
QS 9000: 1998 Obsolete after December 2006--should update
ISO/TS 16949: 2002 Currently available for registration
Daimler Chrysler customers and VDA-6.1
subscribers--by July 2004
Ford/GM Customers--by December 2006
QS 9000 TE Maintain existing registration but be ready
to transition to ISO/TS 16949:2002
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