{"id":1811,"date":"2025-07-22T23:43:01","date_gmt":"2025-07-23T02:43:01","guid":{"rendered":"https:\/\/cuarepoti.com.ar\/recomendaciones-de-aplicacion-de-varillas-y-electrodos-tubulares-para-recargue-duro-hardfacing-2\/"},"modified":"2025-07-25T18:09:15","modified_gmt":"2025-07-25T21:09:15","slug":"recomendaciones-de-aplicacion-de-varillas-y-electrodos-tubulares-para-recargue-duro-hardfacing-2","status":"publish","type":"page","link":"https:\/\/cuarepoti.com.ar\/en\/recomendaciones-de-aplicacion-de-varillas-y-electrodos-tubulares-para-recargue-duro-hardfacing-2\/","title":{"rendered":"Recomendaciones de aplicaci\u00f3n de varillas y electrodos tubulares para recargue duro – hardfacing"},"content":{"rendered":"\t\t
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Application Recommendations for Tubular Rods and Electrodes \u2013 Hardfacing<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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AgroCrom \/ AgroTung<\/strong>
OXI-ACETYLENE APPLICATION GUIDE<\/strong><\/p>

The self-shielded alloy has a melting point of approximately 1050\u202f\u00b0C, making it suitable for application with an oxy-acetylene torch.<\/p>

Required Equipment<\/strong><\/h6>
  • Acetylene and Oxygen cylinders with pressure regulators<\/strong>
    • Oxygen: 4 bar<\/li>
    • Acetylene: 0.8 bar<\/li><\/ul><\/li>
    • Torch tips (approximate consumption \/ diameter):<\/strong>
      • Tip No. 3: 600 L\/h \u2013 \u00d8 1.75 mm<\/li>
      • Tip No. 4: 1000 L\/h \u2013 \u00d8 2.20 mm<\/li>
      • Tip No. 5: 2000 L\/h \u2013 \u00d8 3.00 mm<\/li><\/ul><\/li><\/ul>
        1. Surface Preparation<\/strong><\/h6>
        • Remove rust, dirt, grease, oil, and other contaminants from the surface to be welded.<\/li>
        • Remove any previous hardfacing if:
          • The materials are unknown or incompatible<\/li>
          • There is porosity, cracking, deformation, or work hardening due to impact<\/li><\/ul><\/li>
          • Removal should be done by grinding. Repair the part if necessary.<\/li>
          • A good base is essential\u2014remove fatigued material, protrusions, or surface irregularities.<\/li>
          • Cracks in the base metal must be ground out to reach solid material; drill the ends of the crack and fill with a compatible electrode.<\/li>
          • If the surface has been subjected to impact, remove ~3 mm before rebuilding and hardfacing.<\/li>
          • Poor base metal preparation can lead to weld detachment.<\/li><\/ul>

            If the base metal is unknown or contains harmful elements (e.g., high sulfur):<\/strong>
            Clean the surface and apply a buttering\/intermediate layer using a basic low-alloy electrode (e.g., AWS E-7018) before hardfacing.
            Preparation is even more critical when using a torch.<\/p>

            2. Preheating the Surface<\/strong><\/h6>

            Before hardfacing, the welder should assess the part\u2019s size, shape, properties, and usage.<\/p>

            Recommendations:<\/strong><\/p>

            • Manganese steels:<\/strong> Preheat to 100\u202f\u00b0C but never exceed 260\u202f\u00b0C.
              Higher temperatures (preheat or interpass) may cause manganese carbides to form along austenitic grain boundaries, reducing hardness.<\/li>
            • Cast iron:<\/strong> Requires high preheat temperatures.
              A practical method is heating the part until it reaches a dull red glow.<\/li>
            • Carbon and low-alloy steels:<\/strong>
              Preheating may be necessary to prevent cracking in the base metal or under the bead.<\/li><\/ul>
              3. Hardfacing Procedure<\/strong><\/h6>
              • Use excess acetylene<\/strong> for torch hardfacing. The outer flame should be three times the length of the inner cone<\/strong>.<\/li>
              • A carburizing flame reduces surface melting temperature and protects the base metal from oxidation.
                This is known as the \u201c3X flame<\/strong>\u201d (outer feather = 3\u00d7 cone size).<\/li>
              • Use torch tips from No. 3 to No. 6 depending on rod diameter and part size.
                Nickel-based alloys require a neutral flame<\/strong>.<\/li>
              • Heat the surface until it \u201csweats\u201d (intense red glow), indicating fusion is starting.
                The flame should strike the part at a 45\u00b0 angle<\/strong>, and the rod should approach from the opposite side, also at 45\u00b0.<\/li>
              • Keep the flame oscillating side to side.
                Do not remove the rod tip during fusion.
                Adjust according to desired coating thickness for maximum wear resistance.<\/li><\/ul>

                Welding Position & Bead Direction:<\/strong><\/p>

                • Horizontal position<\/li>
                • Downward direction at 15\u00b0 = thinner deposit<\/li>
                • Upward direction at 15\u00b0 = thicker deposit<\/li><\/ul>

                  Deposit Thickness:<\/strong><\/p>

                  Avoid excessive deposit thickness\u2014it may crack or detach in service.
                  If high thickness is required, use proper rebuilding material first to reach the needed dimensions.<\/p>

                  Rod preheating:<\/strong>
                  Preheat rods for at least one hour at 100\u202f\u00b0C to eliminate moisture and avoid porosity.<\/p>

                  Deformation:<\/strong>
                  Heat may deform parts.
                  Use proper clamping and alternate bead placement to avoid overheating specific areas.<\/p>

                  4. Cooling \/ Postheating<\/strong><\/h6>

                  This method offers excellent dilution control due to the lower flame temperature compared to arc welding, allowing precise fusion and base metal preheat.<\/p>

                  Cooling Procedures:<\/strong><\/p>

                  • Austenitic steels:<\/strong> Minimal interpass temperature needed; cooling is not critical.<\/li>
                  • Martensitic steels:<\/strong> The goal is full martensite formation.
                    • Cool the part in air to ~120\u202f\u00b0C from welding temperature.<\/li>
                    • Maintain the part at 120\u202f\u00b0C for 2\u20133 hours to allow hydrogen to escape and avoid embrittlement.<\/li><\/ul><\/li><\/ul>
                      Postheating<\/strong><\/h6>

                      Postheating generally refers to stress relief and tempering.
                      Performed below critical temperature<\/strong> of the filler material.<\/p>

                      • Typical postheat: 450\u2013650\u202f\u00b0C<\/li>
                      • Time: Approx. 1 hour per 2 cm of part thickness<\/li>
                      • May cause slight hardness drop (1\u20133 HRC), or in some cases increase it due to secondary hardening<\/strong>, often seen during low-temperature tempering.<\/li><\/ul>
                        IMPORTANT SAFETY NOTICE<\/strong><\/h6>

                        Fumes from normal use of these products may contain chromium, manganese, and tungsten carbides<\/strong>, which can be hazardous.<\/p>

                        FLAME SETTINGS<\/strong><\/h6>
                        • Short flame, oxygen excess \u2192 \u274c Not recommended<\/li>
                        • Very long flame, oxygen deficiency \u2192 \u274c Not recommended<\/li>
                        • Short flame, acetylene excess \u2192 \u2705 Recommended, prevents oxidation<\/li><\/ul>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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                          Application Recommendations for Tubular Rods and Electrodes \u2013 Hardfacing AgroCrom \/ AgroTungOXI-ACETYLENE APPLICATION GUIDE The self-shielded alloy has a melting point of approximately 1050\u202f\u00b0C, making it suitable for application with an oxy-acetylene torch. Required Equipment Acetylene and Oxygen cylinders with pressure regulators Oxygen: 4 bar Acetylene: 0.8 bar Torch tips (approximate consumption \/ diameter): Tip […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1811","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/cuarepoti.com.ar\/en\/wp-json\/wp\/v2\/pages\/1811","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cuarepoti.com.ar\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/cuarepoti.com.ar\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/cuarepoti.com.ar\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cuarepoti.com.ar\/en\/wp-json\/wp\/v2\/comments?post=1811"}],"version-history":[{"count":3,"href":"https:\/\/cuarepoti.com.ar\/en\/wp-json\/wp\/v2\/pages\/1811\/revisions"}],"predecessor-version":[{"id":1817,"href":"https:\/\/cuarepoti.com.ar\/en\/wp-json\/wp\/v2\/pages\/1811\/revisions\/1817"}],"wp:attachment":[{"href":"https:\/\/cuarepoti.com.ar\/en\/wp-json\/wp\/v2\/media?parent=1811"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}