Glasby will remain in Melbourne until at least the end of the 2018 season, while Welch has re-signed with the Club for an additional year.
“We are delighted to have re-signed both Tim and Christian, two players who are a big part of this Club moving forward,” Storm Football Director Frank Ponissi said.
“Tim has worked incredibly hard over the last few years to get to where he is and we have no doubt he will continue to improve and take his game to the next level.
“Christian is always looking to learn and he has worked incredibly hard on developing his game to be in regular contention for an NRL spot.
“We look forward to both players being an integral part of our forward pack into the future.”