Extending Valve Life: The Art of Heat Treating and Ceramic Coatings

Transcription

1 Extending Valve Life: The Art of Heat Treating and Ceramic Coatings By Chris Johnson & Kevin Tackett Bodycote Presented at the

2 Today s Valve Industry Today s industrial valve industry within the oil & gas sector is increasingly exposed to greater challenges: Oil discovery in more severe environments Normal erosion, corrosion & friction of valves occurring more frequently More costly practices to comply with new federal regulations Down time to replace/repair a part = money lost As a result, these companies are demanding manufacturers develop parts that last longer. 2

3 Surface Treatment Processes Can aid in extending equipment life by increasing a part s resistance to wear, corrosion and erosion Mature technology that falls into many categories Two categories of particular importance: heat treatment; metallurgical coatings Extend life of parts (i.e. valve bodies and internal components) by as much as 40% Provides valuable savings to companies in terms of time and materials 3

4 Surface Treatment Processes cont... Three unique, yet often unused surface diffusion and overlay coating processes, are making a difference in the oil & gas industry: Boronizing Low Pressure Carburizing (LPC) Ceramic coatings 4

5 Boronizing What is Boronizing? Thermal diffusion surface treatment Boron atoms diffused into surface of a work piece; form borides with base material; increases wear resistance. VERY high surface hardness is achievable Process: Parts packed in a Boronizing powder or painted with a Boronizing paste Placed in a furnace; heated to the range of 1500 o F to 1800 o F under a protective atmosphere; held for a predetermined time (1-8 hours) Parts cooled to room temperatures; un-packed Process similar to carburizing or nitriding; conventional heat treat equipment may be used with modifications Growth is predictable and repeatable for a given part geometry, material and treatment cycle 5

6 Oil & Gas Uses of Boronizing Can be effectively applied to the following: Valve stems, seats and body Grooved drums for textile machinery Diesel engine oil pump gears Extrusion and injection molding augers Barrels Die components Dies of pressing tools used to produce ceramic crucibles: Die life of AISI 02 materials increased 3 times Grinding disks life increased 5 times over non-boronized 1042 Feed water regulating valves: AISI 410 materials last 9 times longer 6

7 Benefits of Boronizing Boronizing boosts corrosion resistance of alloy steels to hydrochloric, sulphuric and phosphoric acids. Results in: Increased tool and mold life Reduced use of lubrication Ability to polish to a high finish Reduced tendency to cold weld Low coefficient of friction Other benefits: Can be applied to a wide range of alloy steels Can selectively applied to only the area that requires hardening, as well as uniformly applied to irregular shapes 7

8 Benefits of Boronizing cont... Low carbon/unalloyed steels exhibit a sawtooth configuration of the boride layer. Higher carbon steel will produce less of a sawtooth interface. 8

9 Benefits of Boronizing cont... High Carbon/Alloy Steels have a more suppressed configuration of the high carbon boride layer (52100 Steel Alloy). 9

10 New Trends With Boronizing Use with carburized surfaces: provides extra push on surface while retaining a ductile core Being used on CRAs, such as Inconel 718 a popular CRA grade within the oil & gas industry Inconel 718 with a surface hardness of VHN 2800 (10 gram force load) 10

11 Low Pressure Carburizing (LPC) Greatly Improved version of old-fashioned vacuum carburizing LPC began evolving in early 1990s Most common gases used: propane and acetylene; use of acetylene results in faster diffusion of carbon, it allows treatment of blind holes as well as loads having greater surface area. Process consists of several boost-diffuse cycles Followed by either gas or oil quench 11

12 Benefits of Low Pressure Carburizing Tighter dimensional control (helps eliminate surface grinding) Clean surface devoid of discoloration Repeatability of process More profiled case depths Process can be performed at higher temperatures No inter-granular oxidation (IGO), which further eliminates surface grinding Higher carbon diffusion into the part No de-alloying Products through LPC demonstrate improved bending and torsional fatigue life; allows diffusion of carbon in deep blind holes All of these benefits result in faster cycle time and reduced overall manufacturing costs. 12

13 Benefits of Low Pressure Carburizing cont... Intergranular Oxidation 13

14 Benefits of Low Pressure Carburizing cont... Surface Oxidation & Finish 14

15 Benefits of Low Pressure Carburizing cont... LPC for Blind Holes 15

16 New Trends With Low Pressure Carburizing Combination with Boronizing to form a duplex layer Creates a new overall heat treatment system Combination achieves extended wear-and-tear life over using either process alone More expensive, but reduces down time in drilling 16

17 Challenges of Low Pressure Carburizing Equipment and infrastructure costs Limited load sizes More complex operation and maintenance is more complex Care in selecting alloys for gas quenching in various section sizes Process modeling tools still in development stage 17

18 Ceramic Coatings / K-Tech What is K-Tech? Thermochemically formed ceramic coating Prevents wear & corrosion in a wide variety of severe industrial applications, including complex geometric shapes and internal bores 3 groups of K-Tech ceramics: Thin film (less than thick) Thick film (0.002 to thick) Diffusion ( to ) Slurry application best used where common wear solutions fail Can be a stand alone or work in conjunction with other metallurgical coatings 18

19 Ceramic Coatings / K-Tech How does K-Tech work? Applied as a slurry to a prepared surface of a machined component Slurry is thermo-chemically converted into a ceramic via a low-temperature firing Chemical reaction creates a chemical-diffusion bond between the chromium (in the coating) and the metallic oxides in the substrate Subsequent processing fill inherent porosity with yet more chromium oxide Results in a dense, wear- and corrosion-resistant coating 19

20 Ceramic Coatings / K-Tech Cross-Section with Chemical Bond Coating Diffusion Bond 4140 Substrate 20

21 Oil & Gas Uses of K-Tech K-Tech is an ideal solution for the following: Valves (stems, seats, gates, balls, body and bonnets) Petroleum (wire line, FMT, MWD unit components/pulsars, mud motors) Pumps (plungers, cylinder liners) Plastic extrusion (screws, barrels) Textiles (precision gear pumps, fiber guides, godet rolls) Glass (fluorescent tubing mandrels) 21

22 Benefits of K-Tech K-Tech has numerous benefits for the oil & gas industry: Increases life of critical components up to 25 times longer Presents an excellent sealing surface Can operate in temperatures up to 2000 F and pressure environments up to 30,000 PSI Impervious to carbon dioxide (erosive) and hydrogen sulfide (corrosive) Prevents hydrogen embrittlement, thereby eliminating sulfide stress cracking (or crevice corrosion cracking) Prevents wear and corrosion from attacking underlying substrate materials (i.e. Inconel, Hastelloy, 4140, 316 stainless steel, 17-4 ph, etc.) 22

23 K-Tech Success in Drilling Sector Motor rotors historically coated with hard chrome plating to prevent wear & corrosion; works well in mild environments (less than 150,000 PPM calcium chloride) But, drilling environments have become more corrosive (calcium chlorides in excess of 250,000 PPM); chrome does not work Porous Propensity to crack K-Tech ceramics seal porosity and cracking problem; stops path for corrosive environment to penetrate to substrate material and undermine chrome plate Improved drilling hours: 50 hours up to hours Industry also moving toward High-Velocity Oxygen Fuel (HVOF)-applied Tungsten Carbide for greater wear & corrosion protection, but same porosity issue appears K-Tech ceramics seal this porosity; extended drilling hours by as much as 1,400 hours 23

24 K-Tech Success in Drilling Sector cont... Increase in abrasion resistance for HVOF-WC with Tech17 Weight Loss (mg) ASTM G-65 Abr. Test HVOF no seal HVOF + Tech-17 24

25 K-Tech Success in Drilling Sector cont... Sealing Effect on HVOF Coatings & Hard Chrome Plate 25

26 K-Tech Success in Drilling Sector cont... Hard Chrome Plate (cross-section) Densification solutions penetrate micro-cracks down to substrate. Subsequent firing forms spinel/chemical bond underneath plating. 26

27 Boronizing Applications in Oil & Gas Sector 300 Series of Stainless Steel Most often used in oil & gas valves Corrosion resistant, but lacks in wear resistance Boronizing creates stronger wear-resistant surface, while not negatively impacting the strong anti-corrosion factor of the 300 series Results in longer lasting component without having to use a more expensive base material Bodycote performs this process daily for numerous oil & gas companies 27

28 Boronizing Applications in Oil & Gas Sector cont... Prematurely Failing Pump Worldwide leader in oil & gas exploration had a prematurely failing pump that was a prototype for off-shore equipment Failure was expensive Bodycote increased the wear by adding a Boronized layer to the carburized surface of the pump and valve components Process greatly extended the life of the part & avoided complete pump redesign 28

29 LPC Applications in Oil & Gas Sector Developing the Improved PSI Valve Stakes continually rising in the oil & gas industry; capabilities of materials being pushed Valve manufacturer recently made a 30,000 PSI valve uncharted territory for this company Bodycote recommended LPC during the manufacturing process LPC s carbon profile and absence of IGO provided superior mechanical properties needed to support the valve design 29

30 K-Tech Applications in Oil & Gas Sector Solving the most severe wear and corrosion problems Bodycote is an industry leader in K-Tech ceramics Several coating solutions developed to solve severe wear & corrosion problems that alternative coatings were unable to address Tech12 ceramic combined with a Boron-Carbide PVD-applied coating to provide excellent corrosion resistance (Tech12) and superior wear resistance (PVD); solved a severe wear & corrosion problem of the ball and seat in a specific steam application Tech17 ceramic combined with a ceramic thermal spray to seal and enhance the performance of the thermal spray; solved the severe corrosion & wear problem of the ball and seat in a specific nickel-smelting application 30

31 Looking Ahead Continued growth into aggressive operating environments Wear and corrosion issues will increase Improving and extending the operational life of critical components used in today s oil fields will become even more important Will require companies and industry experts working together to understand current/future challenges to engineer the solutions of tomorrow 31

32 Questions... What questions can we answer for you? 32

33 Thank you for your time 33

34 VMA Technical Seminar &