{"id":8487,"date":"2026-08-14T10:37:28","date_gmt":"2026-08-14T03:37:28","guid":{"rendered":"https:\/\/giaanh.vn\/?post_type=kien-thuc&p=8487"},"modified":"2026-10-08T10:06:26","modified_gmt":"2026-10-08T03:06:26","slug":"part-2-4-operating-factors-matching-conditions-with-materials","status":"publish","type":"kien-thuc","link":"https:\/\/giaanh.vn\/en\/knowledge\/four-influencing-factors-and-the-material-selection-sequence\/","title":{"rendered":"Part 2: Four influencing factors and the material selection sequence"},"content":{"rendered":"

Knowing that particles are harder than the surface and can cut into the material addresses only one part of the selection problem.<\/p>\n

At an actual operating location, three other factors also need to be considered simultaneously: temperature, impact, and corrosion<\/strong>. The important point is that these four factors are not simply added together. Each factor plays a different role in eliminating or retaining material groups during the selection process.<\/p>\n

Therefore, even when all field measurements are correct, following the wrong screening sequence can still lead to the selection of an unsuitable material group<\/strong>.<\/p>\n

1. The roles of four factors in the selection process<\/span><\/h2>\n

The four factors to be considered include:<\/p>\n

    \n
  • abrasion<\/strong><\/li>\n
  • temperature<\/strong><\/li>\n
  • impact<\/strong><\/li>\n
  • corrosion<\/strong><\/li>\n<\/ul>\n

    During material selection, these four factors are not treated equally.<\/p>\n\n\n\n\n\n\n\n\n
    Factor<\/strong><\/th>\nRole in the selection process<\/strong><\/th>\n<\/tr>\n<\/thead>\n
    Temperature<\/strong><\/td>\nEliminate material groups that can no longer operate within the actual temperature range<\/td>\n<\/tr>\n
    Abrasion<\/strong><\/td>\nEstablish the lower hardness limit<\/td>\n<\/tr>\n
    Impact<\/strong><\/td>\nEstablish the upper hardness limit<\/td>\n<\/tr>\n
    Corrosion<\/strong><\/td>\nFurther eliminate options from the remaining material groups<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    1.1. Temperature is checked first because it can eliminate an entire material group<\/span><\/h3>\n

    A material group may be suitable in terms of hardness or abrasion resistance, but if the temperature at the location exceeds its operating limit, the remaining advantages are insufficient to retain that group as an option.<\/p>\n

    Therefore, the upper operating temperature limit<\/strong> needs to be checked before comparing other properties.<\/p>\n

    1.2. Abrasion establishes the lower hardness limit, while impact establishes the upper limit<\/span><\/h3>\n

    Abrasive wear caused by scratching particles requires the surface to be sufficiently hard relative to the particles acting on it.<\/p>\n

    Impact, however, establishes an upper limit. As hardness increases, the ability to deform and absorb impact may decrease.<\/p>\n

    This creates two boundaries:<\/p>\n

      \n
    • lower hardness limit<\/strong>: the minimum hardness required to limit particle cutting of the surface<\/li>\n
    • upper hardness limit<\/strong>: the maximum hardness that can be used before the material no longer has sufficient toughness for the impact conditions<\/li>\n<\/ul>\n

      If the lower hardness limit exceeds the upper hardness limit, a single material may not satisfy both requirements simultaneously.<\/p>\n

      This result does not mean that the selection process is incorrect. It indicates the need to consider combining multiple material groups or changing the conditions acting on the location<\/strong>.<\/p>\n

      You can learn more about the relationship between hardness, toughness, and the applicable limits of each parameter in Part 1: Material properties and trade-offs in material selection<\/strong>.<\/p>\n

      2. Four groups of data are required before evaluating material options<\/span><\/h2>\n

      The selection process is only meaningful when the input data accurately reflect the conditions at the location.<\/p>\n

      At a minimum, the following need to be recorded:<\/p>\n\n\n\n\n\n\n\n\n
      Factor<\/strong><\/th>\nRequired data<\/strong><\/th>\n<\/tr>\n<\/thead>\n
      Abrasion<\/strong><\/td>\nParticle size, particle hardness, solids concentration, flow velocity<\/td>\n<\/tr>\n
      Temperature<\/strong><\/td>\nOperating temperature and peak temperature<\/td>\n<\/tr>\n
      Impact<\/strong><\/td>\nDrop height, maximum lump size, impact frequency<\/td>\n<\/tr>\n
      Corrosion<\/strong><\/td>\nMoisture content, pH, chemical composition<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      Omitting one factor does not merely make the result less accurate. Each omitted data group can lead to a different type of incorrect material selection.<\/p>\n

      For example:<\/p>\n

        \n
      • failure to record peak temperature may result in retaining a material group whose temperature limit has already been exceeded<\/li>\n
      • failure to record lump size or drop height may result in selecting an excessively hard material for a location subjected to severe impact<\/li>\n
      • failure to record the chemical environment may overlook the risk of corrosion<\/li>\n
      • failure to determine particle hardness leaves the lower hardness limit without a sufficient basis<\/li>\n<\/ul>\n

        If sufficient data are not yet available, the appropriate approach is to return to the survey stage rather than filling in missing information with assumptions.<\/p>\n

        3. Step 1: Eliminate material groups that do not meet the temperature requirements<\/span><\/h2>\n

        Operating temperature and peak temperature are used to eliminate material groups that no longer fall within a suitable operating range.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n
        When the temperature exceeds<\/strong><\/th>\nMaterial groups to eliminate during initial screening<\/strong><\/th>\n<\/tr>\n<\/thead>\n
        80 \u00b0C<\/strong><\/td>\nPolymeric materials<\/td>\n<\/tr>\n
        250 \u00b0C<\/strong><\/td>\nConventional wear-resistant steels<\/td>\n<\/tr>\n
        350 \u00b0C<\/strong><\/td>\nCast basalt, standard-grade cast ceramics and porcelain, bimetallic steel, hard cast alloys<\/td>\n<\/tr>\n
        400 \u00b0C<\/strong><\/td>\nStandard-grade hard compounds<\/td>\n<\/tr>\n
        550 \u00b0C<\/strong><\/td>\nSmooth stainless steel<\/td>\n<\/tr>\n
        750 \u00b0C<\/strong><\/td>\nAll metallic material groups<\/td>\n<\/tr>\n
        1,000 \u00b0C<\/strong><\/td>\nStandard-grade alumina ceramics, cast zirconium-corundum ceramics<\/td>\n<\/tr>\n
        1,200 \u00b0C<\/strong><\/td>\nHeat-resistant hard compounds, sintered zirconium-corundum ceramics<\/td>\n<\/tr>\n
        Above 1,200 \u00b0C<\/strong><\/td>\nHigh-temperature ceramic groups remain, such as silicon carbide and certain high-purity alumina grades<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

        The temperature thresholds above are used for screening by material group<\/strong> and do not replace the technical specifications of individual grades.<\/p>\n

        Within the same group, individual grades may have significantly different temperature limits. After narrowing down the material groups, the current technical documentation for the intended grade still needs to be consulted.<\/p>\n

        4. Step 2: Establish the lower hardness limit according to abrasion severity<\/span><\/h2>\n

        After eliminating material groups that are unsuitable in terms of temperature, the next step is to compare the hardness of the abrasive particles with the hardness of the remaining material groups<\/strong>.<\/p>\n

        If the particles are harder than the surface, they can still cut into the surface and remove material.<\/p>\n

        This does not mean that the material must be eliminated immediately. However, the person making the selection needs to clearly understand that the surface remains softer than the particles and that the scratching mechanism has not been eliminated.<\/p>\n

        In that case, service-life evaluation must be based on these actual conditions rather than assuming that a material described as \u201cwear-resistant\u201d can no longer be affected by the particles.<\/p>\n

        You can learn more about comparing particle hardness with material hardness, as well as the differences between Mohs, Brinell, Vickers, and declared value categories, in Part 1: Material properties and trade-offs in material selection.<\/strong><\/p>\n

        5. Step 3: Establish the upper hardness limit according to impact conditions<\/span><\/h2>\n

        This step proceeds in the opposite direction to the abrasion-resistance requirement.<\/p>\n

        Greater drop height, larger lump size, and higher impact frequency increase the requirements for toughness and impact resistance<\/strong>.<\/p>\n

        If hardness is continually increased solely to resist abrasion, the material may move outside the range suitable for the impact conditions.<\/p>\n

        An indication requiring attention is a change in failure mode from progressive thickness loss due to wear<\/strong> to cracking or spalling<\/strong>.<\/p>\n

        In that case, the following need to be rechecked:<\/p>\n

          \n
        • drop height<\/li>\n
        • maximum lump size<\/li>\n
        • impact frequency<\/li>\n
        • impact resistance of the material<\/li>\n<\/ul>\n

          This failure mode indicates that the problem is no longer simply one of \u201cinsufficient hardness.\u201d<\/p>\n

          6. Step 4: Continue screening according to corrosion conditions<\/span><\/h2>\n

          After temperature, abrasion, and impact have been evaluated, the remaining material groups are further assessed according to the actual chemical environment.<\/p>\n

          Three required data points include:<\/p>\n

            \n
          • moisture content<\/strong><\/li>\n
          • pH<\/strong><\/li>\n
          • chemical composition<\/strong><\/li>\n<\/ul>\n

            If the environment changes significantly with the season, the data also need to be considered under the corresponding operating conditions at each point in time.<\/p>\n

            Dry-season data should not automatically be used to represent rainy-season conditions if moisture content or material condition has changed significantly.<\/p>\n

            Similarly, describing a material as \u201ccorrosion-resistant\u201d or \u201cchemically inert\u201d is only meaningful when associated with a specific environment<\/strong>.<\/p>\n

            7. After the four screening steps, the result generally falls into four cases<\/span><\/h2>\n

            The selection process does not necessarily have to return a single material group.<\/p>\n\n\n\n\n\n\n\n\n
            Result<\/strong><\/th>\nMeaning<\/strong><\/th>\nNext course of action<\/strong><\/th>\n<\/tr>\n<\/thead>\n
            One group remains<\/strong><\/td>\nThe conditions have clearly narrowed down the options<\/td>\nDevelop a specific solution<\/td>\n<\/tr>\n
            Multiple groups remain<\/strong><\/td>\nSeveral options are technically suitable<\/td>\nCompare service life, installation feasibility, and budget<\/td>\n<\/tr>\n
            No single group meets all requirements<\/strong><\/td>\nThe requirements at the location are conflicting<\/td>\nConsider combining multiple material groups<\/td>\n<\/tr>\n
            Insufficient data<\/strong><\/td>\nInput data are insufficient for selection<\/td>\nReturn to the survey stage<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

            If multiple groups remain, the next step is not to continue eliminating options until only one material name remains. The options can be further compared based on:<\/p>\n

              \n
            • expected service life<\/li>\n
            • installation feasibility<\/li>\n
            • fastening method<\/li>\n
            • equipment downtime<\/li>\n
            • budget<\/li>\n<\/ul>\n

              If no single group meets all requirements, you can learn more about dividing the working surface into zones and addressing transition areas in Part 5: Combining multiple materials at one location: design principles and interface control<\/strong>.<\/p>\n

              8. Material-group selection table according to operating conditions<\/span><\/h2>\n

              The table below is intended for screening and relative comparison between material groups<\/strong>, not for use as a calculation formula.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
              Material group<\/strong><\/th>\nAbrasion resistance<\/strong><\/th>\nUpper temperature limit<\/strong><\/th>\nThermal shock<\/strong><\/th>\nImpact<\/strong><\/th>\nMaximum flow velocity<\/strong><\/th>\nPoints requiring attention<\/strong><\/th>\n<\/tr>\n<\/thead>\n
              Wear-resistant steel, quenched and tempered plate<\/strong><\/td>\n+++<\/td>\nApproximately 250 \u00b0C, with heat-resistant grades up to approximately 500 \u00b0C<\/td>\n++<\/td>\n+++<\/td>\nNot specified<\/td>\nCan be welded, bent, and formed<\/td>\n<\/tr>\n
              Powder-sintered bimetallic steel<\/strong><\/td>\n++++<\/td>\n350 \u00b0C, with heat-resistant grades up to 750 \u00b0C<\/td>\n+++<\/td>\n+++<\/td>\n20 m\/s<\/td>\nHigh abrasion and impact resistance among metallic materials<\/td>\n<\/tr>\n
              Hard cast alloys<\/strong><\/td>\n++++<\/td>\n350 \u00b0C<\/td>\n+++<\/td>\n++<\/td>\n20 m\/s<\/td>\nCan be cast into complex, self-supporting shapes<\/td>\n<\/tr>\n
              Fused cast basalt<\/strong><\/td>\n+++<\/td>\n350 \u00b0C<\/td>\n+<\/td>\n+<\/td>\n20 m\/s<\/td>\nHardness of approximately 8 Mohs, durable smooth surface<\/td>\n<\/tr>\n
              Cast ceramics, porcelain<\/strong><\/td>\n++<\/td>\n350 \u00b0C, with heat-resistant grades up to 1,000 \u00b0C<\/td>\n+<\/td>\n+<\/td>\n20 m\/s<\/td>\nSmooth surface<\/td>\n<\/tr>\n
              Cast zirconium-corundum ceramics<\/strong><\/td>\n++++<\/td>\n1,000 \u00b0C<\/td>\n++<\/td>\n++<\/td>\n30 m\/s<\/td>\nDurable smooth surface, corrosion-resistant<\/td>\n<\/tr>\n
              Sintered zirconium-corundum ceramics<\/strong><\/td>\n+++<\/td>\n1,200 \u00b0C<\/td>\n+++<\/td>\n++<\/td>\n25 m\/s<\/td>\nBetter thermal-shock resistance than cast grades<\/td>\n<\/tr>\n
              High-alumina ceramics<\/strong><\/td>\n++++<\/td>\n1,000 \u00b0C, with high-purity grades up to 1,400 \u00b0C<\/td>\n+<\/td>\n+<\/td>\n30 m\/s<\/td>\nCan be manufactured from 1.5 mm thickness<\/td>\n<\/tr>\n
              Nitride-bonded silicon carbide ceramics<\/strong><\/td>\n+++<\/td>\n1,550 \u00b0C<\/td>\n++++<\/td>\n+<\/td>\n25 m\/s<\/td>\nHigh upper temperature limit and thermal-shock resistance<\/td>\n<\/tr>\n
              Silicon-infiltrated silicon carbide ceramics<\/strong><\/td>\n++++<\/td>\n1,250 \u00b0C<\/td>\n++++<\/td>\n++<\/td>\n35 m\/s<\/td>\nHighest flow-velocity range in the table<\/td>\n<\/tr>\n
              Hard compounds, sprayed, trowelled, or cast<\/strong><\/td>\n++++<\/td>\n400 \u00b0C, with heat-resistant grades up to 1,200 \u00b0C<\/td>\n++<\/td>\n++<\/td>\n20 m\/s<\/td>\nDo not create numerous joints; can be repaired in situ<\/td>\n<\/tr>\n
              Smooth stainless steel<\/strong><\/td>\n++<\/td>\n550 \u00b0C<\/td>\nNot rated<\/td>\n++<\/td>\nNot specified<\/td>\nCan be used where abrasion and material sticking occur simultaneously<\/td>\n<\/tr>\n
              Polymeric materials<\/strong><\/td>\n+<\/td>\n80 \u00b0C<\/td>\nNot rated<\/td>\nNot rated<\/td>\nNot specified<\/td>\nHigh material-flow promotion capability, lightweight<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

              The +<\/strong> symbols in the table represent a relative comparison scale between material groups, not a unit of measurement.<\/p>\n

              \u201cNot rated\u201d means that the technical documentation does not evaluate that parameter for the corresponding group; it does not mean that the capability is zero.<\/p>\n

              The velocity in the table refers to material-flow velocity<\/strong>, not conveyor-belt speed or equipment rotational speed.<\/p>\n

              9. Damage patterns can guide measurements before sufficient data are available<\/span><\/h2>\n

              When sufficient measurements are not yet available, surface damage patterns can help determine which parameters should be checked first<\/strong>.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n
              Observed indication<\/strong><\/th>\nMechanism to consider<\/strong><\/th>\nData requiring verification<\/strong><\/th>\n<\/tr>\n<\/thead>\n
              Parallel marks aligned with the flow direction<\/td>\nAbrasive wear caused by scratching particles<\/td>\nParticle size, particle hardness<\/td>\n<\/tr>\n
              Indentations with craze cracking around the indented areas<\/td>\nFatigue wear under impact loading<\/td>\nDrop height, lump size<\/td>\n<\/tr>\n
              Uniform, fine surface ripples aligned with the flow direction<\/td>\nAbrasive wear caused by particle-laden flow<\/td>\nFlow velocity, solids concentration, angle of incidence<\/td>\n<\/tr>\n
              Scattered pitting without a clear directional pattern<\/td>\nChemical action<\/td>\nMoisture content, pH, chemical composition<\/td>\n<\/tr>\n
              Widespread lining detachment after a period of operation<\/td>\nBoth the fastening system and environmental conditions need to be checked<\/td>\nTemperature, moisture content, solids concentration<\/td>\n<\/tr>\n
              Wear and material build-up occurring at the same location<\/td>\nTwo problems occurring simultaneously<\/td>\nBoth wear data and material-sticking data<\/td>\n<\/tr>\n
              Damage over a large area, with multiple joints failing simultaneously<\/td>\nThe influence of the lining structure needs to be considered<\/td>\nArea, geometry, and installation method<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

              This table only helps determine the direction of further investigation. The final conclusion must still be based on data from the actual operating location.<\/p>\n

              10. Example of applying the complete selection sequence<\/span><\/h2>\n

              Assume that an iron ore silo during the rainy season operates under the following conditions:<\/p>\n

                \n
              • particle hardness of approximately 6 Mohs<\/strong><\/li>\n
              • temperature at ambient conditions<\/li>\n
              • material falling from a conveyor at a moderate drop height<\/li>\n
              • seasonally high moisture content<\/li>\n<\/ul>\n

                The sequence can be applied as follows:<\/p>\n

                Step 1 \u2013 Temperature:<\/strong> no significant material groups are eliminated based on the temperature conditions.<\/p>\n

                Step 2 \u2013 Abrasion:<\/strong> particles with a hardness of approximately 6 Mohs establish a surface-hardness requirement.<\/p>\n

                Step 3 \u2013 Impact:<\/strong> the impact severity is not high, so the upper hardness limit remains relatively broad.<\/p>\n

                Step 4 \u2013 Corrosion and moisture:<\/strong> the moist environment further narrows down the remaining material groups.<\/p>\n

                According to the example in the source, the groups retained for consideration include cast basalt or ceramics<\/strong>.<\/p>\n

                This is an example of how to apply the screening sequence, not a general recommendation for every iron ore silo. When the data at the location change, the selection result may also change.<\/p>\n

                11. Responsibilities of the departments<\/span><\/h2>\n\n\n\n\n\n\n\n\n
                Activity<\/strong><\/th>\nPerson or department responsible<\/strong><\/th>\n<\/tr>\n<\/thead>\n
                Record the four groups of input data<\/td>\nSurvey engineer<\/td>\n<\/tr>\n
                Carry out the screening process and identify material groups<\/td>\nMaterials engineer or solution provider<\/td>\n<\/tr>\n
                Confirm that the operating conditions accurately reflect actual conditions<\/td>\nOperations supervisor at the location<\/td>\n<\/tr>\n
                Compare and select among the remaining options<\/td>\nOperating party<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                The verification of operating conditions directly determines the reliability of the entire process.<\/p>\n

                Even a correct selection table can lead to an unsuitable solution if the input data do not accurately reflect the actual operating conditions.<\/p>\n

                12. Notes when applying this knowledge<\/span><\/h2>\n

                First<\/strong>, the plus signs in the table indicate only relative comparison levels between material groups. The plus signs must not be used as quantities in calculations.<\/p>\n

                Second<\/strong>, the temperature thresholds are presented by material group. Within the same group, individual grades may have different limits. Once the material groups have been narrowed down, the current technical specification for the specific grade needs to be consulted.<\/p>\n

                Third<\/strong>, the selection sequence in this article first determines technical suitability<\/strong>; it does not directly establish the most economically advantageous solution. Service life, budget, and shutdown cycles need to be evaluated in the next step.<\/p>\n

                Fourth<\/strong>, installation feasibility is not fully reflected in the selection table. A material group that is suitable for the operating conditions may still be unsuitable for the equipment geometry, fastening method, or available downtime.<\/p>\n

                The selection sequence can be summarized in four steps: temperature eliminates material groups that can no longer operate under the conditions, abrasion establishes the lower hardness limit, impact establishes the upper hardness limit, and corrosion further narrows down the options. When the input data are complete and accurately verified at the location, this process helps narrow a very broad list of materials down to a number of groups with a technical basis for further comparison.<\/p>\n","protected":false},"featured_media":8768,"parent":8485,"menu_order":2,"template":"","meta":{"_acf_changed":false,"inline_featured_image":false},"danh-muc-kien-thuc":[],"class_list":["post-8487","kien-thuc","type-kien-thuc","status-publish","has-post-thumbnail","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/giaanh.vn\/en\/wp-json\/wp\/v2\/kien-thuc\/8487","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/giaanh.vn\/en\/wp-json\/wp\/v2\/kien-thuc"}],"about":[{"href":"https:\/\/giaanh.vn\/en\/wp-json\/wp\/v2\/types\/kien-thuc"}],"up":[{"embeddable":true,"href":"https:\/\/giaanh.vn\/en\/wp-json\/wp\/v2\/kien-thuc\/8485"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/giaanh.vn\/en\/wp-json\/wp\/v2\/media\/8768"}],"wp:attachment":[{"href":"https:\/\/giaanh.vn\/en\/wp-json\/wp\/v2\/media?parent=8487"}],"wp:term":[{"taxonomy":"danh-muc-kien-thuc","embeddable":true,"href":"https:\/\/giaanh.vn\/en\/wp-json\/wp\/v2\/danh-muc-kien-thuc?post=8487"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}