There's no function/event ingame, that for ingots offers you a chance to get (more) ingots. Only transfers available are ingots into coupons, with up to 1:6 ingot:coupon ratio gain at monthly card. SS convoys are close behind with 5.83 gain ratio, but both of those methods arent meant for larger ingot transfers. Normal events we see during the week almost never pass 3:1 gain ratio.