On Friday, December 4th, 2020... SpaceX will attempt the launch of its First, Fully Assembled Starship SN-8 for a Test Flight (HOP) to 15 Kilometers from the Boca Chica Space Port in Texas. Now would be a good time to refer to the Materials and Processes that this HUGE Space Ship is constructed from... with the "Primary Metal" being
304L Stainless Steel. If you want to observe the Test Flight...Here is the Latest News about the Launch:
The remote village of Boca Chica is a place nature has called home. However, the wilderness is sharing its home with a spacecraft and rocket building facility, SpaceX’s Starship facility.
www.click2houston.com
Originally, Elon Musk and his Staff of Engineers had a desire to use
Carbon Fiber constructs for the majority of its major cylinders and super-structures. But he soon discovered that these manufacturing processes would
"...Just take too long...".
The Solution? Initially, he had switched over to
304 Stainless Steel. But after welding up the seams on the Giant Segments in each "Stack" of his early Starship SN-1-5 Test Beds, when joining the enormous cylinders sections together...
the issue of Brittle Carbides precipitating within the welds became a serious concern. The
Carbides reduced the ability of the melted amalgam formed post-welding to resist corrosion and it weakened those bonds in between each one. Having anything assembled on your Space Craft that can be described as
"Being Too Brittle..." is a Very Big No No.
The plot thickened when he opted to get the variant of
304L Stainless Steel, which presents with an adjusted Chemical Mix of Elements that
Reduces the amount of Carbon to an Ultra-Low Level. The placement of an
"L" at the end of the definition of
304L Stainless Steel distinguishes between the two. These changes were also happening at a time when the Machine Welding Methods were being adapted to improve the Quality and Consistency of the Welding Procedures. Here are Two Charts that describe "The Stainless Steel Recipes" comparing
Regular 304 S/S versus 304L S/S:
There is an unfortunate, prevailing 'Mystery' surrounding
EXACTLY what Stainless Steel is that often prompts the Questions,
"How is it Made ?" and
"What are its properties ?". But without doing a little reading from some reliable resources, you won't get any closer to understanding
"WHY?" this choice of metal materials has worked out so well as
"The Metal of Choice for Making Rocket Ships" by Elon Musk for the unique construction of his
Shining, Gleaming SpaceX Starship Machines.
The excellent Properties of these Metals will eventually prove their value and defy our comprehension of just
"How?" these Giant Machines manage to "Hold Together" while Launching... slowly ascending upwards from Boca Chica and then increasing their velocities enough to arrive in Outer Space ...and Safely return to Our Earth.
If you want to get the "Straight Dope" on these issues for your own needs for the use of Stainless Steels... The Links below have been prepared by some of the prime manufacturing companies creating them:
https://www.aksteel.com/sites/default/files/2018-11/304-304l-stainless.pdf
https://www.makeitfrom.com/material-properties/AISI-304L-S30403-Stainless-Steel
https://northlakesteel.com/blog/whats-cold-finished-steel-bar/
https://www.corrosionpedia.com/definition/637/hot-rolling
https://www.convertunits.com/from/MPa/to/psi