The latest development in coatings for heavy iron and steel castings. Tim Birch International Marketing Manager Foseco International Ltd

Transcription

1 The latest development in coatings for heavy iron and steel castings Tim Birch International Marketing Manager Foseco International Ltd

2 Content Introduction Product development for heavy iron and steel castings Fast dry water-based coatings Duplex Coating Single-layer flow coat application The need for control Automatic control of density Effective mixing and coating homogenisation

3 Introduction to Total Coatings Management

4 Identifying the needs of the market Investment in R&D to fulfil the needs of the foundry customer: Increase capability to produce complex, defect-free castings Improve productivity and reduced re-work Reduce overall costs 4.5 million investment in new Foundry R&D Facility (2014) Specialised testing equipment e.g Rheometry, Molten metal facilities, SEM

5 End-to-end process control Delivering Quality & Consistency at all process stages.. To ensure optimum performance at our Customers. Total Coating Management

6 R&D - Delivering new products for heavy iron and steel castings New Products Fast dry water-based coatings Duplex Coating Single-layer flow coat application Automated control Improved mixing New Raw Materials New Process Technology

7 Fast Dry Water-Based Coating Northern Europe Case Study

8 Drying of Larger Components For larger sized components the coating is applied by flow application Historically alcohol based systems are used and flamed-off for quick drying Health and Safety Issues arise

9 Solvents Health, Safety and Environmental Issues Release of VOC s into the environment Respiratory issues relating to solvents Restrictions on storage and use of flammable products ATEX or equivalent certification for associated equipment Ref: European Chemical Agency Website

10 Benefits of water-based products Improved environmental benefits through elimination of solvents Reduced surface cracking of mould due to heat generated in flame-off Reduced burn-out of coating binder BUT : air drying is significantly longer

11 Faster drying water-based products SEMCO FDC - a new range of water-based coatings for flow coating High solids content, with significantly less water to be evaporated off New rheological system allows excellent flow coating at higher solids Layer build equivalent to a traditional coating (zircon, al-silicate or olivine fillers) Elimination of runs and drips Drying time at 25 o C (RH=60%) Excellent casting performance 3 hour (75% solids) 5 hour (65% solids)

12 SEMCO FDC improved productivity and energy saving When used in combination with drying oven fast drying water-based coatings deliver: Improved productivity Reduction in drying energy requirements SEMCO FDC WLT μ Standard WLT μ Oven temperature set to 61 o C Equivalent dry layer thickness

13 SEMCO FDC improved productivity and energy saving Surface Temperature / Moisture Content Time in Oven Standard Coating SEMCO FDC 0 minutes 25 C / 3.9% 25 C / 3.1% 3 minutes 29 C / 3.7% 36 C / 0.7% 6 minutes 40 C / 0.8% 48 C / 0.0% DRY 9 minutes 46 C / 0.4% 12 minutes 48 C / 0.1% DRY Results 50% reduction in drying time 50% reduction in energy

14 SEMCO FDC improved productivity and energy saving

15 Duplex Coating North American Case Study

16 Duplex Coating System For the prevention of metal penetration and burn-on Specifically hot spot areas Undercuts where sand compaction is not optimum Examples of burn-on and severe metal penetration

17 Duplex Coating System Prone areas pre-treated with penetration coating Fine zircon flour based coating (water or solvent based) Penetrates into surface of mould (3-5mm) Minimal surface layer build-up Completely fills all voids between sand grains

18 Duplex Coating System Mould then coated with traditional coating (water or solvent-based) Flow coated Brushed etc If there is a failure of the surface coating layer in critical areas: Mould beneath completely sealed No voids between sand grains for metal to penetrate High refractory material prevents interaction with silica sand

19 Case Study 1: NORAM Iron Jobbing Foundry Significant problem with burn-on and metal penetration on large floor moulds. With HOLCOTE Z-Primer (SEMCO 9223) Clean casting Severe metal penetration and burn-on Note: Top coat is HOLCOTE 950 (al-silicate coating)

20 Case Study 1: NORAM Iron Jobbing Foundry

21 Case Study 2: NORAM Steel Foundry Problem significant metal penetration in flange area Solution ISOMOL Z-primer (TENO ZKPX) Brushed in critical areas Penetration 3-5mm Top coat - ISOMOL (brushed) 2 layers (zircon based coating) Flame Dried between layers

22 Case Study 2: NORAM Steel Foundry Casting Results Dramatic improvement in casting finish Metal penetration and burn-on eliminated Converted floor molding coatings to the duplex coating technology

23 Single Layer Flow Coating for Jobbing Foundries

24 Single Layer Flow Coating for Jobbing Foundries For larger moulds and cores Need to apply multiple coating layers to build-up required layer thickness (>300um) Productivity issues arise: Time for multiple applications Availability of crane Time to use crane (multiple times) Casting quality issues: If done incorrectly the coating layers may de-laminate Brushing leads to inconsistency in layer and brush-marks 24

25 Single Layer Flow Coating for Jobbing Foundries New rheological system allows for: Thick layer (>700um) to be applied in one application Consistent layer build from top-to-bottom of mould surface No slumping No runs and drips No cracking on drying Casting performance equivalent to that achieved with multiple-layer application 2/03/2017 Footnote 25

26 Flow tests Applied wet layer: 1000 μm A wide variety of flow characteristics can be obtained by modifying the formulation 26

27 Example dry layer achieved on furan cores Dry layer 1050 μm Dry layer 830 μm 27

28 Hexagon Block Steel Casting Casting weight: 125 kg Six different coatings 28 28

29 Casting Comparison SemcoCoat SemcoZir 7300B (1x) top layer: 450 μm penetration 5mm bottom (ingate) top R962 Single layer thick coating top layer: 850 μm 29 29

30 In-house casting trials with steel Casting design (severe conditions) Cast weight approx. 210 kg Increased core length 1600,0 Simulation of hexagon test casting: solidification and core temperature 100,0 #4 #3 #2 #1 Temperature [⁰C] 1560,0 80,0 T liquidus 1520 ⁰C 1520,0 60,0 1480,0 40,0 T solidus 1470 ⁰C 1440,0 20,0 1400,0 0,0 0,0 10,0 20,0 30,0 40,0 50,0 60,0 70,0 80,0 Time [min] Core #1 Core #2 Core #3 Core #4 Degree of solidification [%] maximum T steel around core#1 maximum T steel around core#3 Degree of solidification [%] Magma simulation Longer solidification times ( 53 min 65 min) Awaiting casting results

31 Effective Mixing and Coating Control

32 Measurement of dilution and adjustment The effectiveness of a specific coating is controlled by the applied dry layer thickness Too thin and the coating is not effective Too thick and material is wasted, plus risk of: Dimensional issues Scabbing Excessive runs and drips etc Wet layer thickness is a good proxy for dry layer 32

33 Baume vs. Flow Cup Traditionally the application parameters for foundry coatings are defined by Baume or Flow Cup viscosity related to applied layer Both methods open to operator interpretation Measurement technique Supplier of measurement device (specifically Baume) Local standards (DIN, Ford, ISO etc..) 33

34 Layer Thickness variation Baume Flow Viscosity Lowest actual Baume = um Highest actual Baume = um Lowest actual Viscosity = 13.5 sec 260um Highest actual Viscosity = 16.5 sec 410um 34

35 The Limitations of Baume and Flow Viscosity These measurements attempt to measure the combined influence of Solids Content (or dilution) Rheological effect of the gel For Baume termed Body For Flow Cup the viscosity If we eliminate the need to measure rheology. Batch-to-batch consistency from supplier Correct homogenisation of product.an improved measurement technique can be adopted. 35

36 Density measurement variations Flow cup and Baume incorporate the coating rheology into the measurement If we have consistency of rheology from the supplier Density becomes the most effective measurement Density measured in range of +/ g/ml Density measurement of a coating With variation of +/ g/ml Variation in applied layer of +/- 10um 36

37 Continuous Density Measurement Automatic Density Measurement Proven method of continuous density measurement Provides coating density measurement to 3 decimal places Complete homogenisation of the prepared coating Coating density versus time Courtesy: Atlantis Foundry (Halberg), S.Africa 37

38 Conclusions Minimise scrap and re-work in the most cost effective manner Ensure the coating you use is rheologically stable with time Apply most protection where it is needed Z-Primer Improve your productivity Fast drying water-based products Single layer flow coating to high layer thickness Reduce your energy consumption Fast drying water-based products Ensure you apply a sufficient protective layer every time Automated density control and coating homogenisation 2/03/2017 Footnote 38

39 Questions Thank-you for your attention Acknowledgements: Christoph Genzler Bruce Lundeen Martien Haanepen Europe - Product Manager (Coatings) North American - Product Manager (Mould & Core) R&D Scientist 39