{"id":13501,"date":"2026-05-11T07:58:17","date_gmt":"2026-05-11T07:58:17","guid":{"rendered":"https:\/\/www.jstconsultancy.cz\/?p=13501"},"modified":"2026-07-31T21:57:29","modified_gmt":"2026-07-31T21:57:29","slug":"do-we-need-a-vacuum-furnace-with-a-diffusion-pump-for-post-processing-in-am-technologies","status":"publish","type":"post","link":"https:\/\/intelligent-kalam.80-240-27-133.plesk.page\/en\/do-we-need-a-vacuum-furnace-with-a-diffusion-pump-for-post-processing-in-am-technologies\/","title":{"rendered":"Do we need a vacuum furnace with a diffusion pump for post processing in AM technologies?"},"content":{"rendered":"

An interesting list of standards related to HIP<\/strong> and AM technologies\u00a0<\/strong>is published on the Quintus website. (https:\/\/quintustechnologies.com\/partnership\/application-center\/material-densification\/hip-standards\/<\/a>).<\/p>\n

These are split into categories:<\/p>\n

PM-HIP
\n<\/strong>\"\"<\/a><\/p>\n

MIM
\n<\/strong>\"\"<\/a><\/p>\n

EQUIPMENT
\n<\/strong>\"\"<\/a><\/p>\n

CAST
\n<\/strong>\"\"<\/a><\/p>\n

AM
\n<\/strong>\"\"<\/a><\/p>\n

From a detailed point of view, it is clear that the basic types of material are repeated here: Inconel 718, Inconel 625, Ti6Al4V, 17-4PH, AISI 316 L, usually used for applications in the aerospace industry, combustion turbines, implantology, etc. In addition to these steels, it is also possible to consider tool steels such as H13 (1.2344), Dievar, HSS M2 (1.3343), Alloy HX, or in the case of MIM<\/strong> with AISI 4140 powder (42CrMo4, 42CrMo4,\u00a0 1.7225).<\/p>\n

As far as post-heat treatment is concerned, we do not find details in these standards. These are found in SAE<\/strong> or ASTM<\/strong> standards. And if we are looking for an answer to the question of what type of furnace we should use for these processes, we will find them in these standards.<\/p>\n

\"\"<\/a>
\nTable 1<\/u><\/em><\/strong> \u2013 Content of individual standards for AM technologies<\/em><\/p>\n

Janusz Kowalewski from Ipsen has published this table of working pressures in a vacuum furnace, if we want to start with these processes at all.\u00a0https:\/\/www.linkedin.com\/posts\/janusz-kowalewski-99b6275_vacuumfurnace-heattreatingprocersses-vacuumheattreatment-share-7454905425751257088-PPE6?utm_source=share&utm_medium=member_desktop&rcm=ACoAAAwiV-YBIX5g8bPKcpmec63IDHkjRKgHkbw<\/a><\/p>\n

\"\"<\/a>
\nTable 2<\/u><\/em><\/strong> \u2013 Vacuum required for heat treatment processes from Janusz\u00a0<\/em><\/p>\n

However, this table is not supported by standards. If we want to find this data accurately, we need to go to the corresponding standards. They are no longer so tolerant, because they do not say from-to, but at least \u2013 see the table.<\/p>\n

\"\"<\/a>
\nTable 3<\/u><\/em><\/strong> \u2013 Applicable standards for basic types of materials in aerospace production <\/em><\/p>\n

From the point of view of the furnace design, if the target vacuum is \u2264 10<\/strong>\u207b\u2074<\/strong> mbar <\/strong>\u2192 diffuse\u00a0 is mandatory. This is exactly the case \u00a0with Ti6Al4V<\/strong> and INC718. <\/strong><\/p>\n

If the target vacuum is \u2264 10<\/strong>\u207b<\/strong>\u00b3<\/strong> mbar <\/strong>\u2192 diffuse\u00a0 is required<\/strong>. The combination of a primary vacuum pump and a Roots pump theoretically meets these conditions, but in practice it is not so certain. This is one of the reasons why the starting pressure for most non-aerospace applications starts at 10-1 mbar<\/strong>. The influence of sorbence and natural contamination of the furnace usually do not allow us to do more.<\/p>\n

However, there is another criterion that we must take into account. AM parts need better vacuum than formed or cast parts<\/strong><\/p>\n

    \n
  1. Rougher surface \u2192 larger surface area \u2192 more adsorbed H<\/strong>\u2082O<\/strong>\/O<\/strong>\u2082<\/strong><\/li>\n
  2. Residues of baked powder \u2192 local oxidation<\/strong><\/li>\n
  3. Open porosity \u2192 oxygen gets deeper<\/strong><\/li>\n
  4. Higher sensitivity to surface defects (fatigue)<\/strong><\/li>\n<\/ol>\n

    Therefore, it is recommended for AM<\/strong> parts\u00a0 to have a vacuum one order of magnitude better<\/strong> than the minimum standard. The standards are therefore unambiguous: it is not possible without a diffusion vacuum pump<\/strong>. AM parts require:<\/strong><\/p>\n