بررسی تاثیر دما و زمان لحیم کاری سخت بر اتصال ساندویچی فولاد زنگ نزن

ﺑﺮای ﺗﻮﻟﯿﺪ ﻣﺒﺪلﻫﺎی ﺣﺮارﺗﯽ ﺻﻔﺤﻪای، ﺻﻔﺤﺎت ﻓﻮﻻد زﻧﮓ ﻧﺰن ﺑﻪﺻﻮرت ﺳﺎﻧﺪوﯾﭽﯽ ﺑﻪ ﯾﮑﺪﯾﮕﺮ ﻣﺘﺼﻞ ﻣﯽﺷﻮﻧﺪ. ﺑﺮای اﯾﻦ ﻧﻮع اﺗﺼﺎل ﻣﯽﺗﻮان از روش ﻟﺤﯿﻢ ﮐﺎری ﺳﺨﺖ ﮐﻪ در آن اﺗﺼﺎل دﻫﯽ ﺗﺤﺖ ﺧﻸ ﺻﻮرت ﻣﯽﮔﯿﺮد، اﺳﺘﻔﺎده ﻧﻤﻮد. ﺑﻪﻫﻤﯿﻦ ﻣﻨﻈﻮر در اﯾﻦ ﻃﺮح، ﺻﻔﺤﺎت ﻓﻮﻻد زﻧﮓ ﻧﺰن 316 l ﺑﻪﺻﻮرت ﭼﻨﺪ ﻻﯾﻪ 2 و 5 ﻻﯾﻪ ﺗﻮﺳﻂ ﻻﯾﻪ واﺳﻄﻪ ﻣﺲ ﮐﻪ ﻧﺴﺒﺖ ﺑﻪ ﺳﺎﯾﺮ ﻓﻠﺰات ﭘﺮﮐﻨﻨﺪه ﻣﻘﺮون ﺑﻪﺻﺮﻓﻪﺗﺮ و دارای دﻣﺎی ذوب ﭘﺎﯾﯿﻦﺗﺮ اﺳﺖ و اﻣﮑﺎن اﯾﺠﺎد اﺳﺘﺤﮑﺎم اﺗﺼﺎل ﻧﺴﺒﺘﺎ ﻣﻨﺎﺳﺐ دارد، ﺑﻪ ﯾﮑﺪﯾﮕﺮ ﻣﺘﺼﻞ ﺷﺪﻧﺪ. ﻣﺘﻐﯿﺮﻫﺎی اﯾﻦ ﭘﮋوﻫﺶ، دﻣﺎ 1070 و 1120 درﺟﻪ ﺳﺎﻧﺘﯽﮔﺮاد و زﻣﺎن 60 ،30 و 90 دﻗﯿﻘﻪ ﺑﻮد. ﺗﺼﺎوﯾﺮ ﻣﯿﮑﺮوﺳﮑﻮﭘﯽ ﮐﻪ ﺑﺮای ﺑﺮرﺳﯽ رﯾﺰﺳﺎﺧﺘﺎر درز اﺗﺼﺎل ﮔﺮﻓﺘﻪ ﺷﺪ، ﻧﺸﺎن داد ﮐﻪ اﺗﺼﺎل اﯾﺠﺎد ﺷﺪه در دﻣﺎی 1070 درﺟﻪ ﺳﺎﻧﺘﯽﮔﺮاد ﻧﺴﺒﺖ ﺑﻪ 1120 درﺟﻪ ﺳﺎﻧﺘﯽﮔﺮاد ﻣﻨﺎﺳﺐ و ﯾﮑﭙﺎرﭼﻪ ﻧﺒﻮده و اﺗﺼﺎل در دﻣﺎی 1120 درﺟﻪ و زﻣﺎن 90 دﻗﯿﻘﻪ ﺑﻪدﻟﯿﻞ ﻓﺮﺻﺖ ﮐﺎﻓﯽ ﺑﺮای ذوب ﻻﯾﻪ واﺳﻄﻪ و ﻧﻔﻮذ ﻋﻨﺎﺻﺮ، ﺧﻮاص ﺑﻬﺘﺮی داﺷﺖ. ﻫﻤﭽﻨﯿﻦ ﻧﻤﻮﻧﻪﻫﺎی دوﻻﯾﻪ ﺑﺎ ﻣﺘﻮﺳﻂ اﻧﺪازه داﻧﻪ ﮐﻤﺘﺮ، ﺳﺨﺘﯽ ﺑﺎﻻﺗﺮی داﺷﺘﻨﺪ.

investigating the effect of brazing time and temperature on stainless steel sandwich joints

brazing of low-carbon austenitic stainless steel sheets is applied to produce plate heat exchangers. in this study, the copper filler was used to join multiple layers of 316l steel plates due to its low cost, low melting temperature and relatively good bonding strength compared to other filler metals. for comparison, 2-layer and 5-layer specimens were brazed with the copper interlayer. fabricated. the sandwich joints have been fabricated under different process conditions of the brazing temperature (1070 and 1120°c) and the brazing time (30, 60, and 90 min). detailed microstructural studies and hardness were carried out on the brazed joints. the microscopic studies showed that the joint formed at 1070 °c was not uniform compared to 1120 °c and the specimen brazed at 1120°c/90 min presented better properties due to enough time for melting of the interlayer and diffusion of elements. also, 2-layer specimens with lower average grain size had higher hardness than 5-layer specimens.