AA GMA69-2016 Guidelines for Handling Molten Aluminum (Fourth Edition).pdf

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1、GUIDELINES FOR HANDLING MOLTEN ALUMINUMFOURTH EDITIONMAY 201669iGuidelines for Handling Molten AluminumFourth Edition - 2016Editor Curt Wells, The Aluminum AssociationEditorial BoardBrad Burridge NovelisJim Brock AlcoaVincent DiCerbo ConstelliumMark Eliopulos Kaiser AluminumLes Kirby Aluminum Cast S

2、hop Consultants, LLCJake Niedling ConsultantJack Patrick Sapa Ray Richter Aluminum Cast Shop Consultants, LLCJeff Wiesner AlcoaJohn Zeh Logan AluminumMike Zoll NovelisThe guidelines and recommendations in this book are based on information believed to be reliable and are offered in good faith but wi

3、thout guarantee. The precise causes of molten metal explosions, and the conditions under which problems arise, have been long studied but are still not fully understood. The operational conditions which exist in individual plants and facilities vary widely, and thus no definitive standards exist for

4、 handling molten aluminum. Accordingly, the Aluminum Association and its member companies assume no responsibility or liability for the completeness of the data or the general applicability of the guidelines and recommendations herein, which are based on state of the art knowledge but may not be app

5、ropriate in all situations. The photographs in this publication are illustrative only and are not intended to represent standard safety practices utilized in the industry. Users of these Guidelines should adapt the recommendations herein, as appropriate, to the precise conditions of the individual f

6、acility under consideration and should always exercise independent discretion in establishing plant or facility operating procedures. No warranty, express or implied, is made of this information by the Aluminum Association or by any of its member companies. Copyright 2016, The Aluminum Association,

7、Inc.Unauthorized reproduction by photocopy or any other means is illegalii ForewordThe original Guidelines were first issued by the Aluminum Association in 1980, quickly followed by a first revision in 1982. In 1990, a second edition was published which presented information and practices available

8、up to that time. In 2002, a third edition was released which was reflective of the ongoing evolu-tion of molten metal safety management programs. It is clear from the revision history noted above that practices and equipment for melting and casting aluminum are continually being modified and improve

9、d for a variety of reasons. In addition, information from industry reporting programs and research efforts spearheaded by the Aluminum Association and its member companies is continually being generated Therefore, in order to capture and disseminate updated information in these areas, these guidelin

10、es undergo periodic review and revision toward the goal of making the aluminum industry workplace safer.This fourth edition of the Guidelines was prepared with technical input and review by industry representa-tives with considerable expertise in all aspects of handling molten aluminum. Basic inform

11、ation has been retained, but considerable change has been made to the organization and presentation of the subject matter. New sections have been added and the existing sections have been significantly updated and expanded to incorporate the new information available since publication of the third e

12、dition. In particular, new information has been added on 1) the management of the hazards presented by combustible aluminum dust, 2) the unique hazards of managing aluminum-lithium alloys, and 3) mobile equipment safety in the casthouse.iiiTable of ContentsContributors . iForeword . iiI. INTRODUCTIO

13、N .1Section 1: Introduction .3Section 2: Scope, Format, and Organization of the Guidelines 4II. SAFETY MANAGEMENT .5Section 3: Safety Programs and Training .7III. GENERAL INFORMATION AND DESIGN CONSIDERATIONS .9Section 4: Hazards in Handling Molten Aluminum General . 11Section 5: Physical and Chemic

14、al Properties of Molten Aluminum . 11Section 6: Suggested Purchase Specifications for Charge Materials . 12Section 7: Receiving, Inspection, Storage, and Drying of Scrap and all other Components of the Furnace Charge 12Section 8: Melting, Melt Treatment and Transfer, and Casting Processes . 13Sectio

15、n 9: Considerations in Design of Equipment and Controls . 18Section 10: Housekeeping 25IV. PERSONAL PROTECTION 27Section 11: Personal Protective Clothing and Equipment 29V. MELTING, MELT TREATMENT, AND TRANSFER OPERATIONS . 39Section 12: Receiving, Inspection, and Storage of Materials to be Melted 4

16、1Section 13: Pre-melting Precautions . 42Section 14: Drying of Material Charged into the Furnace . 46Section 15: Handling and Processing of Sow, T-Ingot and Billet 48Section 16: Melting Operations including Treatment of Metal in the Furnace 50Section 17: In-line Melt Treatment Operations 53Section 1

17、8: Melt Transfer Operations General 54Section 19: Metal Transfer during Casting of Process Ingot 56VI. CASTING OPERATIONS . 59Section 20: SOPs for Casting and Precasting Precautions . 61Section 21: Casting of Process Ingot General 63Section 22: Direct Chill (DC) Casting Conventional 63iv Section 23:

18、 Hot Top Casting / Level Pour Casting . 66Section 24: Electromagnetic Casting (EMC) . 69Section 25: Aluminum Lithium Casting 72Section 26: Other Casting Systems . 75Section 27: Cleanup of Metal Spills . 75VII. PROTECTIVE COATINGS: CASTING PITS AND EQUIPMENT . 77Section 28: Protective Coatings for Ca

19、sting Pits and Equipment . 79VIII. CASTHOUSE MOBILE EQUIPMENT . 81Section 29: Casthouse Mobile Equipment . 83Section 30: Pedestrian Interaction / Segregation 83Section 31: Equipment Specifications 84Section 32: Qualification, Training and Evaluation . 86Section 33: Operating Guidelines 87IX. EXPLOSI

20、ONS INVOLVING MOLTEN ALUMINUM 89Section 34: Explosions Involving Molten Aluminum 91Section 35: Thermite Reactions 92Section 36: Research on Molten Aluminum-Water Explosions . 93Section 37: Molten Metal Incident Reporting 97X. EXPLOSIONS INVOLVING COMBUSTIBLE DUST . 99Section 38: Combustible Dust in

21、the Casthouse 101Section 39: Hazards . 101Section 40: Preventive Measures: . 103Section 41: Dust Incident Response 103XI. REFERENCES AND TRAINING AIDS 105Section 42: References 107Section 43: Videos and Training Aids on Preventing Molten Aluminum-Water Explosions 109vFigures1 Figure 1 Aerial view of

22、 a casthouse following a molten metal explosion .31 Figure 2 Ground level view of a casthouse following a molten metal explosion 48.1 Figure 1 Charging a Furnace from a Transfer Crucible 138.2 Figure 2 Typical Melting, Holding, Casting Process Flow Sheet. 148.3.5 Figure 1 One Type of Continuous Stri

23、p Casting Machine 168.3.6 Figure 1 A Robotic Pig Ingot Casting Machine with Skimming and Metal Filling Control . 178.3.6 Figure 2 A Modern Sow Casting Operation . 179.3.4 Figure 1 Billet Base Plate with Starting Blocks . 219.3.4 Figure 2 DC Casting Pit with Low Water Level in Pit . 229.3.4 Figure 3

24、DC Casting Pit with High Water Level in Pit 2211.2.2 Figure 1 Secondary Protective Clothing 3011.2.2 Figure 2 Aluminized Primary Protective Clothing 3111.2.2 Figure 3 Zirpro Wool Primary Protective Clothing . 3111.2.2 Figure 4 Aluminized Primary PPE in Casthouse Use . 3111.2.4 Figure 1 Face shield t

25、hat protected employee from eye damage and facial burns during a drain pan molten metal explosion . 3311.3 Figure 1 FR garments worn by employee exposed to molten metal from a drain pan explosion. Use of FR garments minimized the extent of burn injuries. 3411.3 Figure 2 Graph of Casting Explosions b

26、y Casting Segment 3411.3 Figure 3 Photo sequence showing an end of cast drain pan explosion in progress. Use of proper PPE prevented significant employee injury. . 3513.1.1 Figure 1 Examples of cavities, cracks and double poured sows that can contain moisture. . 4213.1.2 Figure 1 Examples of cavitie

27、s and cracks that can contain moisture and a double poured sow. 4313.1.3 Figure 1 Examples of oxidized copper and magnesium, magnesium shrinkage cavity . 4413.1.3 Figure 2 Example of a zinc ingot with a shrinkage cavity 44vi 13.2 Figure 1 Salt flux on top of and imbedded into RSI. The dark material

28、identified by the arrow was found to be flux salt. . 4514.1 Figure 1 Example of a commercially available sow drying system. The system shown is a natural gas fired dryer with positive pressure and recirculation fans. 4816 Figure 1 Melting explosions data 5116 Figure 2 Force Level Explosions by Opera

29、tion . 5116.4 Figure 1 Skimming Dross from a Furnace by Mechanical Skimmer . 5218.4.Figure 1 Force Level Explosions by Operation . 5518.4 Figure 2 Injuries by Operation . 5518.4 Figure 3 Transfer Explosions by Equipment Type Involved 5620 Figure 1 DC/HDC/EMC Explosions by Cast Segment 6122.1 Figure

30、1 Typical DC Casting Station Billet 6422.1 Figure 2 Typical DC Casting Station Slab/Sheet Ingot 6422.2 Figure 1 Schematic of Horizontal DC Casting Station . 6522.2 Figure 2 Section of Horizontal DC Casting Station and Water Basin 6523.1 Figure 1 Schematic of a Hot Top DC Casting System 6723.1 Figure

31、 2 Schematic of Hot Top Mold with Air Injection . 6724.2 Figure 1 Typical Automated EM/DC Casting Sequence 7024.3.2 Figure 1 Automated Safety Stops in EM/DC Casting 7131.1 Figure 1 Charging Scrap into a Remelt Furnace Using a Shielded Fork Truck 8531.1 Figure 2 Fork Truck Following a Furnace Explosi

32、on 8531.1 Figure 3 Foundry Package Equipped Fork Truck in Use . 8534 Figure 1 Explosion Characterization 9137 Figure 1 Molten Metal Incident Reporting Form . 9838 Figure 1 Aluminum Dust/Fines 10139 Figure 1 The Fire Triangle . 10139 Figure 2 The Explosion Pentagon . 10240 Figure 1 Aluminum Dust Clou

33、d . 103INTRODUCTIONIINTRODUCTION 3Section 1 IntroductionAs evidenced by globally available injury and illness statistics gathered by the Aluminum Association and other sources, aluminum plants are relatively safe, healthy workplaces. However, every industry has its potential hazards depending on the

34、 processes and/or products involved. The aluminum industry is no exception. Billions of pounds of aluminum are melted and cast safely every year in cast shops, foundries, recycling and reclamation plants all over the globe. However, there are inherent hazards in handling molten aluminum, just as the

35、re are in virtually any activity. These hazards can be minimized and eliminated by careful attention to safe handling practices. Failure to use proper procedures in melting and casting aluminum can be dangerous. Contact with molten aluminum can burn personnel or set materials on fire. Mixing water a

36、nd many chemical substances or contaminants with molten aluminum can cause explosions. These explo-sions can range widely in violence and can result in injury or death as well as significant destruction of equipment and plant facilities. Examples of the damage resulting from catastrophic molten meta

37、l explosions in the aluminum industry are shown in 1 Figure 1 and 1 Figure 2.1 Figure 1 Aerial view of a casthouse following a molten metal explosion 4 INTRODUCTIONSection 2 Scope, Format, and Organization of the Guidelines2.1: ScopeThese Guidelines were prepared for use by all personnel concerned o

38、r associated with activi-ties involving molten aluminum, and particularly for those involved in everyday plant operations. All major steps in remelting, treating, trans-ferring, and casting molten aluminum and its alloys are discussed, excluding potline opera-tions in reduction plants. Details are n

39、ot given on specific operating practices for proprietary melting, melt treatment, and casting systems. For information on specific safety procedures for these systems, please consult the vendors of those systems. Emphasis is placed on large-scale melting and casting practices for the production of p

40、rocess ingot. Slabs or billets produced are subsequently mechanically worked into forms such as sheet, plate, foil, forgings, or extrusions. Alternately, cast shapes such as T-bar, sow, and Remelt Scrap Ingot (RSI) may be produced and then shipped offsite for remelting at another site. Information i

41、s also provided on scrap remelting activities. Terminology used in these guidelines reflects that employed in the industry.2.2: FormatThe wire bound format of the Guidelines is intended to allow the publication to lie flat for ease of reference to the information and to allow for easy copying of rel

42、evant sections for use as handouts at safety and training meetings.2.3: OrganizationThe revised Guidelines consist of eleven parts. The presentation of material under headings of both general information and specific pro-cedures results in some repetition. This was done deliberately to be reflective

43、 of the refer-ence nature of this material so as to allow it to be read in individual sections for reference to specific information needed at a point in time rather than in a front-to-back cover to cover style as would be done in a traditional book format.1 Figure 2 Ground level view of a casthouse

44、 following a molten metal explosionSAFETY MANAGEMENTIISAFETY MANAGEMENT 7Section 3 Safety Programs and Training3.1: Safety-GeneralExperience shows that the best safety records in industries of all kinds exist where safety is given the same level of importance and attention as quality, production, an

45、d cost. This means safety can and must be actively led and managed to achieve a safe workplace.As in the case of newer approaches used to achieve outstanding improvements in product quality, successful management of accident prevention goes beyond simple directives from supervision to the work force

46、. Success in safety comes from the implementation of a safety man-agement system that includes the fundamentals of plan, do, check and act. The diagram below represents a typical management system model.This model represents a continuous cycle of improvement. One goes through a planning process to d

47、ecide what safety exposures they want to reduce and determine what resources are needed to make that happen. One takes actions in the plan to reduce exposure. One evaluates the impact of the actions taken. One decides if the desired reduction in risk occurred or not. If yes, the cycle starts anew by

48、 revising the plan to target new exposures. If the desired risk reduction was not achieved, the plan is modified to include new actions to reduce the exposure.This model has direct application to managing molten aluminum risk. Assume a site is con-cerned about a molten metal explosion triggered by p

49、utting sows that may have water/moisture on or in them into a melting furnace. The site should identify the risks associated with this activity in the planning phase of the management system. The site also can set objectives to reduce the risk, as well as the action items necessary to make that hap-pen. The site will need to provide the re-sources needed to implement the actions. This is followed by taking action; one exam-ple of which could be installing sow dryers. Once the actions are taken, the site should then decide if the actions taken p