Q245R　steel　has　good　heat　and　corrosion　resistant　and　is　used　in　various　applications,　such　as　reactors,　regenerators,　reformed　gas　steam　generators,　and　other　equipment.　In　this　study,　the　creep　behaviour　of　Q245R　steel　at　the　temperature　of　550　℃　is　investigated.　In　addition　to　the　modified　Kachanov-Robotnov　(K-R)　method,　the　traditional　and　modified　θ　projection　methods　were　employed　to　establish　the　creep　constitutive　equations　of　Q245R　steel.　The　results　revealed　that　at　small　strains,　the　creep　prediction　curve　was　in　good　agreement　with　the　test　curve,　and　the　prediction　accuracy　of　the　modified　θ　projection　method　was　better　than　that　of　the　other　two　models.　©　2023　Informa　UK　Limited,　trading　as　Taylor　&　Francis　Group.