Not really, no. There is really a whole world of difference between the modern metallurgy and the metalworking processes and techniques available to people in pre-industrial era more or less anywhere. Also, speaking of Vikings, we need to observe that they did not really have that bigger access to ice or cold water, as they lived in relatively warm regions capable of supporting agriculture and the shores of the Baltic and North Sea are characterized by a relatively mild, maritime climate, with winters in the more continental regions of Europe being more severe.

I'm not really knowledgeable about marketing practices of the toolmakers, but the process known as 'ice-hardening' or 'deep freeze hardening' really exists and means bringing the worked item to very low temperatures after quenching to increase its hardness before the item is tempered. These are very often complex criogenic processes and temperatures used make them unfeasible to replicate with the the medieval methods, as they usually reach -70 to -90°C (-95 to -130°F) but may require temperatures as low as -150°C (-240°F), and mind that this is the temperature actually reached by the worked item, not just the freezing medium.

Having said that, we might look upon the possibility of using criogenic techniques available to people in the Viking Age. Ice or the large ice block would be useless for quenching as the whole point of this process is to cool down the entire item rapidly, what would be impossible in this case as the red-hot metal would melt through ice at very low pace or, if the blacksmith wanted to use more strength, it would end with ice shattering to pieces. Ice water could be used as a medium, and it could have even have measurable effect, as the ice would help to keep the temperature of the quenching agent lower for a longer time, but it would possibly require modern laboratory equipment to measure and would not be possible to observe it practically, not to mention that for this difference to matter, the item must have been made heated to a very precisely measured temperatures, what prior to modern industrial thermometers was not feasible.

Would it matter even if the early medieval smiths somehow had a possibility to generate such temperatures? Again, not really. Even modern 'ice-quenching' techniques using temperatures indicated above allow for the increase of 2-3 HRC. On one hand, this would mean increase of 8-10% in hardness, but this would be beneficial to a modern, uniform steel. Weapons made in pre-industrial times could have shown a very large heterogeneity not only between e.g. the edge and core, but also in various points of the same longitudinal cross-sections. Hardness spanning from 19-58 HRC (220-560 HRC) was not unusual in the blades from the 10th-11th century (I have chosen these, as they would fit the 'Viking age' mentioned here).

It should have been also noted, that prior to 16th century steel or iron swords were usually not quenched thoroughly, as is is common practice today. In many modern documentaries or shows about blacksmithing, you might often see that the blacksmith heats the steel object to a high temperature (usually 800-1050°C or 1.500-1.900°F) cools it rapidly by quenching in water or oil (but remember that after quenching, both blade and quenching agent are hot, with water often being brought to a boil) and then temper the object by keeping it heated to a much lower temperature (usually around 220°C or 451 °F, which is the flashpoint of paper as we all know thanks to Ray Bradbury) for up to few hours. This process did not become commonplace until 18th century, although has been utilized in a high-quality products as early as early 16th century. Blacksmiths in the discussed period usually resorted to 'slack-quenching' or quick, partial quenching, usually at temperatures similar to those metal was worked at (closer to 800°C), not followed by tempering. This made process easier, lowered chances of warping of breaking and increased flexibility of the object, but also significantly lowered the overall hardness of the blade. In such circumstances, usage of ice water would have done nothing to increase the quality of the blade in comparison to a regular room-temperature water.

Examination of the 41 sword blades including 14 'Ulfbehrt' swords and 301 spearheads found in the Baltic sites, dated to 6th-10th century CE and analyzed by Aleksis Anteins in 1968 have shown average hardness of blades to be 250-330 HV or 25-36 HRC. Such values are hardly impressive and are a good evidence that the weapons made by the people inhabiting shores of the Baltic sea in the period largely corresponding to the 'Viking Age' were not of superior quality and thus they were not made according to any techniques that would have significantly improved the quality of the produced weapons.

So, to sum it up, modern 'ice-quenching' is a complex technological process generating temperatures unavailable in the pre-industrial times. It also requires a very high quality of material and controlled environment that has not been achieved until relatively recent times and thus would be of no use to people who did not have access to such well-processed material and precise techniques.

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Craddock, P.T., Early Metal Mining and Production. Smithsonian Institution Press, Edinburgh 1995.

Edge, W., Williams, A.R., Some Early Medieval Swords in The Wallace Collection and Elsewhere in: Gladius, vol. XXIII, 2003, pp. 191-210.

Lang, J., Williams, A.R., The Hardening of Iron Swords, in: Journal of Archaeological Science, 1975, vol. 2, pp. 199-207.

Williams, A.R., The Knight and the Blast Furnace. Brill, Boston 2003.