Lub valve yog ib qho tseem ceeb ntawm lub cav thiab ua haujlwm nyob rau hauv cov xwm txheej hnyav heev:
Qhov kub thiab txias: Qhov kub ntawm lub valve tuaj yeem ncav cuag 650-850 degree
Kev kub siab: Kev txom nyem los ntawm kev cuam tshuam ntawm kev tawg siab
Corrosion: Oxidation thiab corrosion los ntawm siab -kub roj (muaj sulfur thiab lead)
Abrasion: nquag cuam tshuam thiab kev sib txhuam nrog lub rooj zaum valve
Fatigue: Cov neeg kho tshuab qaug zog thiab thermal qaug zog tshwm sim los ntawm kev rov qhib thiab kaw
Yog li ntawd, lub valve steel yuav tsum muaj:
High thermal zog thiab hardness: Tsis softening ntawm kub kub thiab tuav lub zog siab
oxidation kuj zoo heev: Resisting oxidation los ntawm siab -kub roj
High hnav tsis kam: Resistant rau kev cuam tshuam thiab kev sib txhuam
Zoo thermal qaug zog tsis kam: Tsis tawg nyob rau hauv lub caij txias thiab kub
Toughness: Kev ua tau zoo tsis ua kom tsis zoo nyob rau hauv ntev - lub sij hawm siab - siv kub
II. Cov kev faib loj thiab cov qhab nia raug
Valve steel feem ntau muab faib ua ob pawg: Martensitic thiab Austenitic:
1. Martensitic valve steel (nruab nrab-tsawg load, nruab nrab kub)
Cov yam ntxwv: Cov ntsiab lus carbon ntau dua (0.4-0.6%), feem ntau muaj Cr thiab Si. Nws tuaj yeem ua kom muaj zog los ntawm quenching + tempering, nrog siab hardness, zoo hnav tsis kam, thiab tus nqi qis.
Kev siv qhov kub thiab txias: ≤ 700 degree, feem ntau yog siv rau cov khoom siv los yog lub teeb -load pa valves.
Hom qeb:
4Cr9Si2 (1.4718): Feem ntau siv, dav - lub hom phiaj valve steel
4Cr10Si2Mo (1.4731): Muaj Mo, nrog zoo dua siab - kub lub zog thiab toughness
2. Austenitic valve steel (siab load, siab kub)
Cov yam ntxwv: High Cr, Ni, thiab ntxiv N, W, Mo, thiab lwm yam. Lub siab - kub lub zog, creep tsis kam, thiab thermal qaug zog tsis kam yog qhov zoo tshaj rau hom martensitic, tab sis tus nqi siab thiab kev ua haujlwm nyuaj.
Kev siv kub: 700-850 degree, feem ntau yog siv rau qhov hnyav-load tso tawm li qub.
Hom qeb:
5Cr21Mn9Ni4N (21-4N): Qhov zoo tshaj plaws classic austenitic valve steel, nitrogen ntxiv dag zog, tus nqi-kev ua tau zoo
23-8N (5Cr23Ni8Mn3N): Siab Cr, zoo heev oxidation kuj
GH4751 (Nimonic 80A): Nickel-raws li siab- kub alloy, siv nyob rau hauv ultra- kub thiab ultra- siab zog scenarios
| C | Cr | Si | Mn | Ni | Mo | N | ||
|---|---|---|---|---|---|---|---|---|
| 4cr9s 2 | 0.35~0.50 | 8.0~10.0 | 2.0~3.0 | - | - | - | - | |
| 4Cr10 Si2Mo | 0.35~0.45 | 9.0~11.0 | 1.9~2.6 | - | - | 0.7~1.0 | - | |
| 21-4N | 0.45~0.60 | 20.0~22.0 | ≤1.0 | 8.0~10.0 | 3.2~4.3 | - | 0.3-0.5 |
4Cr9Si2 Martensitic Thaum tshav kub kub Resistant Steel X45CrSi9-3 (1.4718) ≤700℃Ordinary roj av cav, lub teeb diesel cav intake valve / low-load pa valve
4Cr10Si2Mo Martensitic Heat Resistant Steel X40CrSiMo10-2 (1.4731) ≤750℃Nruab nrab-load diesel cav, tsheb tso valve
5Cr21Mn9Ni4N (21-4N) Austenitic Valve Steel 21-4N 750 ~ 800℃Hnyav tsheb thauj khoom, nkoj, lub zog siab lub cav tso pa valve