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904L super austenitic stainless steel is a kind of high alloyed austenitic stainless steel with very low carbon content. It has good mechanical properties, process properties and strong corrosion resistance. There are practical applications in industrial fields such as processing, oil refining, coking, etc., and can also be used in pressure vessels and other fields. The application in these fields cannot be separated from the support of welding technology. Therefore, the research on its welding performance provides support for its further extensive application. . In this paper, molten inert gas shielded welding (MIG) is used, and the welding wire is ER385 to weld 2mm and 7mm thick 904L super austenitic stainless steel plates respectively. The welding process parameters are changed, and the microstructure of the welded joints is observed and analyzed. At the same time, the hardness test and impact performance mechanical performance test were carried out on the welded joints. Determine the most suitable process parameters, so that the performance of the obtained welded joint can be adapted to the manufacturing and working conditions. The results show that: 904L super austenitic stainless steel is not sensitive to heat input and has no obvious heat affected zone. During the welding process, since the composition of the fusion zone is the remelting combination of the base metal and the welding wire, the solidification composition is different from the base metal and the weld, which is dominated by A mode, and the grain size is small, resulting in poor impact performance of the welded joint. The mechanical properties near the weld fusion zone are relatively good.

The invention relates to the field of hot-rolled steel sheet production, and specifically discloses a hot-rolled steel sheet and a preparation method and application thereof. The microstructure of the hot-rolled steel sheet is an austenite structure and a martensitic structure. The content of morphological austenite structure accounts for more than 20% of the total austenite structure content. The preparation method of the hot-rolled steel sheet provided by the present invention comprises the following steps: heating, rough rolling, finishing rolling and solid solution of the slab formed by forging in sequence; The deformation rate of the finishing rolling is 60-70%, and the deformation rate of the final pass deformation of the finishing rolling is 8-12%. The invention adopts a new controlled rolling process, so that the hot-rolled steel plate has high strength, high plasticity and high toughness at normal temperature, and also has good low temperature and ultra-low temperature properties, and is especially suitable for application in rocket engines.

It is a ferritic-austenitic (duplex) stainless steel that combines the most beneficial properties of many ferritic and austenitic steels and has excellent properties due to its high chromium and molybdenum content. Excellent resistance to pitting corrosion, crevice corrosion and uniform corrosion. The bidirectional microstructure ensures that the steel has high resistance to stress corrosion cracking and high mechanical strength.Stainless steel is used in the oil and gas industry; offshore Shipotian oil platforms (heat exchanger tubes, water treatment and water supply systems, fire protection systems, water spray systems, water stabilization systems; petrochemical equipment; desalination (desalination) equipment (and equipment in High-pressure pipes, seawater pipes); mechanical and structural components that require both high strength and high corrosion resistance; combustion (waste) gas purification equipment. Main components: 25Cr-7Ni-4Mo-0.27NNational standards:ASTM/ASME: A240 - UNS S32750EURONORM:1.4410 - X2CrNiMoN25-7-4AFNOR: Z3 CN 25.06 AzDIN/EN 1.4410, ASME SA-240chemical composition:C≤0.03,Si≤0.80,Mn≤1.2,Cr:24-26,Ni:6-8,S≤0.02,P≤0.035,Mo:3-5,N: 0.24-0.32Application areas: pulp and paper industry, seawater desalination, flue gas purification, heat exchangers, chemical tanker piping systems, seawater systems, etc.

Do you know that Global demand for steel is expected to return to pre-Covid-19 levels in 2021 with the exception of China? as resurgent demand continues to fuel strong manufacturing activityProjects demand to grow 4.5% in 2021 to reach 1,855.4 MT after a tepid 0.1% growth in 2020, with growth further rising by 2.2% to 1,896.4 MTStrong manufacturing activity bolstered by pent-up demand is the main contributorDeveloped economies have outperformed our earlier expectations by a larger margin than the developing economies, reflecting the positive benefit of higher vaccination rates and govt support measuresIn the emerging economies, especially in Asia, the recovery momentum was interrupted by the resurgence of infectionsThe pandemic upended the global economy, forcing industries engaged in steel, including construction, autos and durable goods, to halt projects or scale down manufacturing as demand dried upBut with restrictions largely lifted and economies reopening, industry stakeholders are making up for lost time and keeping up with rejuvenated demandSteel demand recovery in the GCC fell short of expectations on the back of reduced construction activity owing to fiscal consolidation effortsBut with rising oil prices and the pandemic under control, steel demand is expected to rebound more strongly in 2022Demand in China dropped 13.3% in July and 18.3% in August because of the slowing momentum in the real estate sector and the govt cap on steel productionActivity also weakened owing to tough government measures on developers' financing that were introduced in 2020Chinese steel demand will have negative growth for the rest of 2021In the US, demand was aided by the strong performance of the automotive and durable goods sectors, but shortage of some components is undermining this recoveryThe momentum in the construction sector is weakening with the end of a residential construction boom and sluggish non-residential sector activitiesRecovery in the European Union is gathering pace, with all steel-using sectors exhibiting a positive recovery despite continuing waves of infectionJapan's rising exports, investment and consumption have aided steel's recovery, with the manufacturing, automotive and machinery sectors leading the waySouth Korea's steel demand is expected to recover to 2019 levels this year, supported by improving exports and investment in manufacturing facilitiesIn developing economies excluding China, steel demand continued to rebound in 2021, aided by the recovery in commodity prices and international tradeHowever, new Covid waves combined with low vaccination levels and a slow recovery in international tourism restrained developing economiesIndia suffered only a minor downward revision and will show a strong recovery in 2021, with steel demand to reclaim the 100-million-tonne mark this yearWhile the manufacturing sector’s recovery remained more resilient to the new waves of infection than expected, supply-side constraints led to a levelling off of the recovery in the second half of the year and are preventing a stronger recovery in 2021But with high backlog orders combined with a rebuilding of inventories and further progress in vaccinations in developing countries, we expect steel demand will continue to recover in 2022What do you think about the Global Steel Industry?