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Temperature Range - Doxsteel · PDF fileTemperature Range When a fastener is ... steels also...

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  • Temperature RangeWhen a fastener is installed, torquing forces generate heat that can cause its coating to break out or burn away, leaving the bolt vulnerable to corrosion. When we designed Doxsteel Fasteners, we knew that our coating had to be able to take the heat if it was going to resist seizing.

    Every Doxsteel Fastener can operate in temperatures ranging from -328F to 1300F without compromising its coating. ASTM specifications state that coatings working in temperatures higher than one half its melting point are in danger of producing liquid and solid metal embrittlement in the fastener. When compared to other leading coatings with much lower melting points, the difference is clear. In the extreme temperatures that come from torquing, Doxsteel Fasteners keep working.

    281-298-1500 | [email protected] | doxsteel.com1544 Sawdust Rd #301 | The Woodlands, TX 77380

    COATING MELTING TEMP OPERATIONAL TEMPERATURE RAGE

    Cadmium Plating 600F -40 300F

    Hot Dip Zinc 780F -10 390F

    Zinc Plating 780F -10 390F

    Zinc Plating + PTFE 300F -50 150F

    Ceramic + PTFE 300F -50 150F

    Zn-Ni Plating 1472F -10 390F

    doxsteelfasteners 2642F -300 1300F

  • Service temperature of DOX studs.

    This document aims to provide references to the use of the DOX-Steel alloy, under low and high service

    temperatures, as an anticorrosive plating for studs and nuts under ASTM standards such as A193, A194 and

    PEMEX standards as NRE-027 and NRF-032.

    Base material

    Base materials which mainly dox Steel alloy is deposited cover threaded rods, bolts and nuts generally

    manufactured under ASTM different denominations of which some examples are given in Table 1, these

    steels also are detailed in the standard NRF-027 PEMEX-2009 and NRF-032-PEMEX-2005.

    Examples:

    Service temperatures

    Material Minimum Maximus

    C F C F

    ASTM A193 B7 steel -50 -58 450 842

    ASTM A194 2H steel -50 -58 450 842 Table 1. Service temperatures for steel manufacture under ASTM.

    However, DOX-Steel plating can be used on any carbon steel substrate.

    DOX- Steel plating.

    Dox Steel Coating is a nickel-based alloy with high resistance to corrosion, which by its metallic character

    (noble metals) is also resistant to low and high temperatures without suffering changes in its structure, in

    addition to not affect its adhesion to the substrate. The following information details the working

    temperatures DOX-Steel alloy.

  • - Ni-Co phase diagram (Nickel-Cobalt).

    T. Nishizawa and K. Ishida, 1991.

    Figure 1 illustrates the nickel and cobalt phase diagram, the DOX-Steel alloy is indicated in blue.

    Considering the magnetic transition line (magnetic-non magnetic), the alloy use is limited to a

    temperature of 750 C, which is 300 C above the maximum recommended temperature for a B7

    grade steel.

    Figure 1. Ni-Co phase diagram , a diferentes temperaturas y concentraciones de Ni.

    - Potential/pH diagram (Pourbaix [E vs pH]).

    The following diagrams show the thermodynamic stability zones for the DOX-Steel alloy to extreme

    service temperatures

    -200 C

    Figure 2. Potential/pH diagram (Pourbaix) of DOX-Steel alloy at -200 C.

  • 25 C

    Figure 2. Potential/pH diagram (Pourbaix) of DOX-Steel alloy at 25 C.

    700 C

    Figure 2. Potential/pH diagram (Pourbaix) of DOX-Steel alloy at 700 C.

    Figures 2-4 illustrate the Porbaix diagrams where the stability of the DOX-Steel alloy at the pH (0-14)

    and potential (-0.5 to -2.0 V) range where Ni, Co and their borides do not present changes in stability.

    Therefore, the DOX alloy could be used in a wide range of temperature, from low to high without

    presenting changes in its corrosion resistance.

    The diagrams were constructed for the indicated temperatures and an aqueous system.

  • DOX-Steel vs other coatings

    Table 2 presents a brief comparison of service temperatures for the most used coatings in the industry.

    Coating Melting

    temperature (C)

    Service temperature (C)

    Zinc 409 C -25C to 125C

    Cadmium 321C Above 100 C, highly toxic cadmium

    oxides are formed.

    Fluoropolymer 250C -40 C to 233C

    DOX-Steel 1450C -200 C a 700 C Table 2. Comparison between DOX-Steel plating and other highly used coatings. The fluoropolymer can

    work at its maximum temperature intermittently.

    Conclusion.

    The DOX-Steel plating presents service temperatures ranging from -200 C to 700 C for long periods

    of time given that the are no phase changes in its microstructure and thermodinamically speaking, the

    alloy keeps its stability at pH 0-14 and potential from -0.5 to -2.0 V at these temperature values.

    The DOX-Steel alloy by not presenting changes in its microstructure nor in the conforming elements,

    it does not present changes in its high anticorrosive properties or in its adherence to the substrate.

    DOX-Steel plating can be used in an environment with severe temperature changes o under hich

    temperature ambient conditions.

    Table 3 presents the chemical composition and service condition of the DOX-Steel plating.

    DOX-Steel plating

    Chemical composition Service temperature

    % Ni % Co % B Minimal Maximal

    C F C F

    52 46 02 -200 -328 700 1292

    Table 3. Chemical composition and service temperature for DOX-Steel plating.

    Bibliography

    - ASM Metals HandBook Volume 3 - Alloy Phase Diagrams, 1992, USA.

    - ASTM 2004 Volume 01.01 Steel--Piping, Tubing, Fittings, 2004, USA.

    - Normas de NRF-027-PEMEX-2009 y NRF-032-PEMEX-2005 de PEMEX.

    - http://www.metcoat.com/assets/files/Fluorokote1Brochure.pdf

    - http://www.crct.polymtl.ca/ephweb.php

    - http://www.doxsteel.com/storkacidtest.pdf

    - http://es.scribd.com/doc/24616185/CATALOGO-TECNICO-PERNOS-Y-TUERCAS

    http://www.metcoat.com/assets/files/Fluorokote1Brochure.pdfhttp://www.crct.polymtl.ca/ephweb.phphttp://www.doxsteel.com/storkacidtest.pdfhttp://es.scribd.com/doc/24616185/CATALOGO-TECNICO-PERNOS-Y-TUERCAS

  • 1544SawdustRoad,Suite301.TheWoodlands,Texas,77380

    [email protected]@doxsteel.com

    To: Gerardo Verdiguel doxsteelfasteners

    Field Test Date: July 12, 2017 N.C

    R&D MI. Atahualpa Oscar Garca DelgadoMI. Jose Hernandez Espinoza

    1

    Field test report for doxsteelfasteners in a E3404 reboiler in Coatzacoalcos, Veracruz

    Abstract

    It has been demonstrated through field testing of doxsteelfasteners in high temperature-systems installations, that the Ni-Co alloy:

    Does not present seizing problems between the nuts and the studs at high temperature,660 0F and a corrosive environment level C5.

    Even with the use of a lubricant which might generate problems at high temperature, suchas the generation of molybdenum oxides, the nut turned without interference.

    There are no changes on the fasteners functionality. There are no changes on the anticorrosion properties of the plating Does not present a risk for liquid metal embrittlement, contrary to other coatings with low

    melting point such as zinc and cadmium. There are no cutting, grinding, drilling or nut splitting related expenses. There is no downtime related to removing seized bolts, all nuts turn on studs.

    Test conditions:

    The aim of this work was to test and compare the effectiveness of doxsteelfasteners nickel-cobalt alloy anticorrosion plating on fasteners under high temperature and corrosive level conditions, as those presented in a distillation reboiler system.

    Test specimen Dimensions Operating conditions

    Exposure time Location

    ASTM A193 GRADE B7 ALLOY STEEL STUD, STANDARD THREAD ASME B1.1 CLASS 2A AND 2B, WITH TWO ASTM A 194 GRADE 2H HEX CARBON STEEL NUTS, WITH NICKEL-COBALT ALLOY CORROSION RESISTANCE PLATING ASTM B994 SC18 CLASS 1 SR-0, ER-9.

    1 1/8 - 8 X

    17 1/4

    High temperature

    350 0C (660 0F)

    Corrosion environment

    level C5

    2 years Gulf of Mexico

  • 1544SawdustRoad,Suite301.TheWoodlands,Texas,77380

    [email protected]@doxsteel.com

    To: Gerardo Verdiguel doxsteelfasteners

    Field Test Date: July 12, 2017 N.C

    R&D MI. Atahualpa Oscar Garca DelgadoMI. Jose Hernandez Espinoza

    2

    1. Background

    Reboilers are heat exchangers typically used to provide heat to the bottom of industrial distillation columns. Proper operation of the reboiler is vital for effective distillation. Due to all operating conditions this equipment suffer from corrosion at high temperatures.

    The City of Coatzacoalcos, Veracruz, presents one of the most corrosive atmospheres of the Gulf of Mexico, based on studies carried out by different institutes, and taking as a reference the classification of international standards, the corrosiveness of the atmosphere presents levels of C5, i.e. presents very high corrosion by the presence of aggressive agents, such as CO2, SO2, Cl-, S2-, etc.

    High temperature corrosion occurs when a metal is subjected to elevated temperatures normally above 100 C, except for very exceptional cases, it is not possible to form a conductive liquid film (electrolyte) on the surface, so a mechanism of electrochemical corrosion cannot take place, instead a chemical reaction takes place between the metal and the aggressive gaseous environment, usually oxygen. The main corrosion products are metal oxides, this oxide is generated directly on the metal surface, with the circulation of electrons

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